diff --git a/osu.Game.Tests/Visual/Gameplay/TestSceneSpectator.cs b/osu.Game.Tests/Visual/Gameplay/TestSceneSpectator.cs
index d47ebf9f0d..d614815316 100644
--- a/osu.Game.Tests/Visual/Gameplay/TestSceneSpectator.cs
+++ b/osu.Game.Tests/Visual/Gameplay/TestSceneSpectator.cs
@@ -257,7 +257,7 @@ namespace osu.Game.Tests.Visual.Gameplay
             sendFrames();
             waitForPlayer();
 
-            AddStep("send passed", () => spectatorClient.EndPlay(streamingUser.Id, SpectatedUserState.Passed));
+            AddStep("send passed", () => spectatorClient.SendEndPlay(streamingUser.Id, SpectatedUserState.Passed));
             AddUntilStep("state is passed", () => spectatorClient.WatchedUserStates[streamingUser.Id].State == SpectatedUserState.Passed);
 
             start();
@@ -275,7 +275,7 @@ namespace osu.Game.Tests.Visual.Gameplay
             sendFrames();
             waitForPlayer();
 
-            AddStep("send quit", () => spectatorClient.EndPlay(streamingUser.Id));
+            AddStep("send quit", () => spectatorClient.SendEndPlay(streamingUser.Id));
             AddUntilStep("state is quit", () => spectatorClient.WatchedUserStates[streamingUser.Id].State == SpectatedUserState.Quit);
 
             start();
@@ -293,7 +293,7 @@ namespace osu.Game.Tests.Visual.Gameplay
             sendFrames();
             waitForPlayer();
 
-            AddStep("send failed", () => spectatorClient.EndPlay(streamingUser.Id, SpectatedUserState.Failed));
+            AddStep("send failed", () => spectatorClient.SendEndPlay(streamingUser.Id, SpectatedUserState.Failed));
             AddUntilStep("state is failed", () => spectatorClient.WatchedUserStates[streamingUser.Id].State == SpectatedUserState.Failed);
 
             start();
@@ -312,16 +312,16 @@ namespace osu.Game.Tests.Visual.Gameplay
 
         private void waitForPlayer() => AddUntilStep("wait for player", () => (Stack.CurrentScreen as Player)?.IsLoaded == true);
 
-        private void start(int? beatmapId = null) => AddStep("start play", () => spectatorClient.StartPlay(streamingUser.Id, beatmapId ?? importedBeatmapId));
+        private void start(int? beatmapId = null) => AddStep("start play", () => spectatorClient.SendStartPlay(streamingUser.Id, beatmapId ?? importedBeatmapId));
 
-        private void finish(SpectatedUserState state = SpectatedUserState.Quit) => AddStep("end play", () => spectatorClient.EndPlay(streamingUser.Id, state));
+        private void finish(SpectatedUserState state = SpectatedUserState.Quit) => AddStep("end play", () => spectatorClient.SendEndPlay(streamingUser.Id, state));
 
         private void checkPaused(bool state) =>
             AddUntilStep($"game is {(state ? "paused" : "playing")}", () => player.ChildrenOfType<DrawableRuleset>().First().IsPaused.Value == state);
 
         private void sendFrames(int count = 10)
         {
-            AddStep("send frames", () => spectatorClient.SendFrames(streamingUser.Id, count));
+            AddStep("send frames", () => spectatorClient.SendFramesFromUser(streamingUser.Id, count));
         }
 
         private void loadSpectatingScreen()
diff --git a/osu.Game.Tests/Visual/Gameplay/TestSceneSpectatorPlayback.cs b/osu.Game.Tests/Visual/Gameplay/TestSceneSpectatorPlayback.cs
index a4d8460846..4ec46036f6 100644
--- a/osu.Game.Tests/Visual/Gameplay/TestSceneSpectatorPlayback.cs
+++ b/osu.Game.Tests/Visual/Gameplay/TestSceneSpectatorPlayback.cs
@@ -41,8 +41,12 @@ namespace osu.Game.Tests.Visual.Gameplay
 
         private Replay replay;
 
+        private TestSpectatorClient spectatorClient;
+
         private ManualClock manualClock;
 
+        private TestReplayRecorder recorder;
+
         private OsuSpriteText latencyDisplay;
 
         private TestFramedReplayInputHandler replayHandler;
@@ -54,7 +58,6 @@ namespace osu.Game.Tests.Visual.Gameplay
             {
                 replay = new Replay();
                 manualClock = new ManualClock();
-                SpectatorClient spectatorClient;
 
                 Child = new DependencyProvidingContainer
                 {
@@ -76,7 +79,7 @@ namespace osu.Game.Tests.Visual.Gameplay
                                 {
                                     recordingManager = new TestRulesetInputManager(TestSceneModSettings.CreateTestRulesetInfo(), 0, SimultaneousBindingMode.Unique)
                                     {
-                                        Recorder = new TestReplayRecorder
+                                        Recorder = recorder = new TestReplayRecorder
                                         {
                                             ScreenSpaceToGamefield = pos => recordingManager.ToLocalSpace(pos),
                                         },
@@ -143,22 +146,52 @@ namespace osu.Game.Tests.Visual.Gameplay
             });
         }
 
+        [Test]
+        public void TestBasic()
+        {
+            AddUntilStep("received frames", () => replay.Frames.Count > 50);
+            AddStep("stop sending frames", () => recorder.Expire());
+            AddUntilStep("wait for all frames received", () => replay.Frames.Count == recorder.SentFrames.Count);
+        }
+
+        [Test]
+        public void TestWithSendFailure()
+        {
+            AddUntilStep("received frames", () => replay.Frames.Count > 50);
+
+            int framesReceivedSoFar = 0;
+            int frameSendAttemptsSoFar = 0;
+
+            AddStep("start failing sends", () =>
+            {
+                spectatorClient.ShouldFailSendingFrames = true;
+                framesReceivedSoFar = replay.Frames.Count;
+                frameSendAttemptsSoFar = spectatorClient.FrameSendAttempts;
+            });
+
+            AddUntilStep("wait for send attempts", () => spectatorClient.FrameSendAttempts > frameSendAttemptsSoFar + 5);
+            AddAssert("frames did not increase", () => framesReceivedSoFar == replay.Frames.Count);
+
+            AddStep("stop failing sends", () => spectatorClient.ShouldFailSendingFrames = false);
+
+            AddUntilStep("wait for next frames", () => framesReceivedSoFar < replay.Frames.Count);
+
+            AddStep("stop sending frames", () => recorder.Expire());
+
+            AddUntilStep("wait for all frames received", () => replay.Frames.Count == recorder.SentFrames.Count);
+            AddAssert("ensure frames were received in the correct sequence", () => replay.Frames.Select(f => f.Time).SequenceEqual(recorder.SentFrames.Select(f => f.Time)));
+        }
+
         private void onNewFrames(int userId, FrameDataBundle frames)
         {
-            Logger.Log($"Received {frames.Frames.Count} new frames ({string.Join(',', frames.Frames.Select(f => ((int)f.Time).ToString()))})");
-
             foreach (var legacyFrame in frames.Frames)
             {
                 var frame = new TestReplayFrame();
                 frame.FromLegacy(legacyFrame, null);
                 replay.Frames.Add(frame);
             }
-        }
 
-        [Test]
-        public void TestBasic()
-        {
-            AddStep("Wait for user input", () => { });
+            Logger.Log($"Received {frames.Frames.Count} new frames (total {replay.Frames.Count} of {recorder.SentFrames.Count})");
         }
 
         private double latency = SpectatorClient.TIME_BETWEEN_SENDS;
@@ -318,6 +351,8 @@ namespace osu.Game.Tests.Visual.Gameplay
 
         internal class TestReplayRecorder : ReplayRecorder<TestAction>
         {
+            public List<ReplayFrame> SentFrames = new List<ReplayFrame>();
+
             public TestReplayRecorder()
                 : base(new Score
                 {
@@ -332,7 +367,9 @@ namespace osu.Game.Tests.Visual.Gameplay
 
             protected override ReplayFrame HandleFrame(Vector2 mousePosition, List<TestAction> actions, ReplayFrame previousFrame)
             {
-                return new TestReplayFrame(Time.Current, mousePosition, actions.ToArray());
+                var testReplayFrame = new TestReplayFrame(Time.Current, mousePosition, actions.ToArray());
+                SentFrames.Add(testReplayFrame);
+                return testReplayFrame;
             }
         }
     }
diff --git a/osu.Game.Tests/Visual/Multiplayer/TestSceneMultiSpectatorLeaderboard.cs b/osu.Game.Tests/Visual/Multiplayer/TestSceneMultiSpectatorLeaderboard.cs
index 6b3573b3cb..42bb99de24 100644
--- a/osu.Game.Tests/Visual/Multiplayer/TestSceneMultiSpectatorLeaderboard.cs
+++ b/osu.Game.Tests/Visual/Multiplayer/TestSceneMultiSpectatorLeaderboard.cs
@@ -34,7 +34,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
                 foreach ((int userId, var _) in clocks)
                 {
-                    SpectatorClient.StartPlay(userId, 0);
+                    SpectatorClient.SendStartPlay(userId, 0);
                     OnlinePlayDependencies.MultiplayerClient.AddUser(new APIUser { Id = userId });
                 }
             });
@@ -68,10 +68,10 @@ namespace osu.Game.Tests.Visual.Multiplayer
                 // For player 2, send frames in sets of 10.
                 for (int i = 0; i < 100; i++)
                 {
-                    SpectatorClient.SendFrames(PLAYER_1_ID, 1);
+                    SpectatorClient.SendFramesFromUser(PLAYER_1_ID, 1);
 
                     if (i % 10 == 0)
-                        SpectatorClient.SendFrames(PLAYER_2_ID, 10);
+                        SpectatorClient.SendFramesFromUser(PLAYER_2_ID, 10);
                 }
             });
 
diff --git a/osu.Game.Tests/Visual/Multiplayer/TestSceneMultiSpectatorScreen.cs b/osu.Game.Tests/Visual/Multiplayer/TestSceneMultiSpectatorScreen.cs
index 77a06e5746..e5e3fecd06 100644
--- a/osu.Game.Tests/Visual/Multiplayer/TestSceneMultiSpectatorScreen.cs
+++ b/osu.Game.Tests/Visual/Multiplayer/TestSceneMultiSpectatorScreen.cs
@@ -71,11 +71,11 @@ namespace osu.Game.Tests.Visual.Multiplayer
             loadSpectateScreen(false);
 
             AddWaitStep("wait a bit", 10);
-            AddStep("load player first_player_id", () => SpectatorClient.StartPlay(PLAYER_1_ID, importedBeatmapId));
+            AddStep("load player first_player_id", () => SpectatorClient.SendStartPlay(PLAYER_1_ID, importedBeatmapId));
             AddUntilStep("one player added", () => spectatorScreen.ChildrenOfType<Player>().Count() == 1);
 
             AddWaitStep("wait a bit", 10);
-            AddStep("load player second_player_id", () => SpectatorClient.StartPlay(PLAYER_2_ID, importedBeatmapId));
+            AddStep("load player second_player_id", () => SpectatorClient.SendStartPlay(PLAYER_2_ID, importedBeatmapId));
             AddUntilStep("two players added", () => spectatorScreen.ChildrenOfType<Player>().Count() == 2);
         }
 
@@ -134,8 +134,8 @@ namespace osu.Game.Tests.Visual.Multiplayer
                     TeamID = 1,
                 };
 
-                SpectatorClient.StartPlay(player1.UserID, importedBeatmapId);
-                SpectatorClient.StartPlay(player2.UserID, importedBeatmapId);
+                SpectatorClient.SendStartPlay(player1.UserID, importedBeatmapId);
+                SpectatorClient.SendStartPlay(player2.UserID, importedBeatmapId);
 
                 playingUsers.Add(player1);
                 playingUsers.Add(player2);
@@ -361,7 +361,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
             // to ensure negative gameplay start time does not affect spectator, send frames exactly after StartGameplay().
             // (similar to real spectating sessions in which the first frames get sent between StartGameplay() and player load complete)
-            AddStep("send frames at gameplay start", () => getInstance(PLAYER_1_ID).OnGameplayStarted += () => SpectatorClient.SendFrames(PLAYER_1_ID, 100));
+            AddStep("send frames at gameplay start", () => getInstance(PLAYER_1_ID).OnGameplayStarted += () => SpectatorClient.SendFramesFromUser(PLAYER_1_ID, 100));
 
             AddUntilStep("wait for player load", () => spectatorScreen.AllPlayersLoaded);
 
@@ -398,7 +398,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
                     };
 
                     OnlinePlayDependencies.MultiplayerClient.AddUser(user.User, true);
-                    SpectatorClient.StartPlay(id, beatmapId ?? importedBeatmapId);
+                    SpectatorClient.SendStartPlay(id, beatmapId ?? importedBeatmapId);
 
                     playingUsers.Add(user);
                 }
@@ -412,7 +412,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
                 var user = playingUsers.Single(u => u.UserID == userId);
 
                 OnlinePlayDependencies.MultiplayerClient.RemoveUser(user.User.AsNonNull());
-                SpectatorClient.EndPlay(userId);
+                SpectatorClient.SendEndPlay(userId);
 
                 playingUsers.Remove(user);
             });
@@ -425,7 +425,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
             AddStep("send frames", () =>
             {
                 foreach (int id in userIds)
-                    SpectatorClient.SendFrames(id, count);
+                    SpectatorClient.SendFramesFromUser(id, count);
             });
         }
 
diff --git a/osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerGameplayLeaderboard.cs b/osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerGameplayLeaderboard.cs
index 6605f82d5c..cfac5da4ff 100644
--- a/osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerGameplayLeaderboard.cs
+++ b/osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerGameplayLeaderboard.cs
@@ -58,7 +58,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
                 foreach (int user in users)
                 {
-                    SpectatorClient.StartPlay(user, Beatmap.Value.BeatmapInfo.OnlineID);
+                    SpectatorClient.SendStartPlay(user, Beatmap.Value.BeatmapInfo.OnlineID);
                     multiplayerUsers.Add(OnlinePlayDependencies.MultiplayerClient.AddUser(new APIUser { Id = user }, true));
                 }
 
diff --git a/osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerGameplayLeaderboardTeams.cs b/osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerGameplayLeaderboardTeams.cs
index dabc1c1e5a..f751b162d1 100644
--- a/osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerGameplayLeaderboardTeams.cs
+++ b/osu.Game.Tests/Visual/Multiplayer/TestSceneMultiplayerGameplayLeaderboardTeams.cs
@@ -62,7 +62,7 @@ namespace osu.Game.Tests.Visual.Multiplayer
 
                 foreach (int user in users)
                 {
-                    SpectatorClient.StartPlay(user, Beatmap.Value.BeatmapInfo.OnlineID);
+                    SpectatorClient.SendStartPlay(user, Beatmap.Value.BeatmapInfo.OnlineID);
                     var roomUser = OnlinePlayDependencies.MultiplayerClient.AddUser(new APIUser { Id = user }, true);
 
                     roomUser.MatchState = new TeamVersusUserState
diff --git a/osu.Game.Tests/Visual/Online/TestSceneCurrentlyPlayingDisplay.cs b/osu.Game.Tests/Visual/Online/TestSceneCurrentlyPlayingDisplay.cs
index b5a03b558d..35a4f8cf2d 100644
--- a/osu.Game.Tests/Visual/Online/TestSceneCurrentlyPlayingDisplay.cs
+++ b/osu.Game.Tests/Visual/Online/TestSceneCurrentlyPlayingDisplay.cs
@@ -56,9 +56,9 @@ namespace osu.Game.Tests.Visual.Online
         [Test]
         public void TestBasicDisplay()
         {
-            AddStep("Add playing user", () => spectatorClient.StartPlay(streamingUser.Id, 0));
+            AddStep("Add playing user", () => spectatorClient.SendStartPlay(streamingUser.Id, 0));
             AddUntilStep("Panel loaded", () => currentlyPlaying.ChildrenOfType<UserGridPanel>()?.FirstOrDefault()?.User.Id == 2);
-            AddStep("Remove playing user", () => spectatorClient.EndPlay(streamingUser.Id));
+            AddStep("Remove playing user", () => spectatorClient.SendEndPlay(streamingUser.Id));
             AddUntilStep("Panel no longer present", () => !currentlyPlaying.ChildrenOfType<UserGridPanel>().Any());
         }
 
diff --git a/osu.Game/Online/Spectator/OnlineSpectatorClient.cs b/osu.Game/Online/Spectator/OnlineSpectatorClient.cs
index ddde69c627..4d6ca0b311 100644
--- a/osu.Game/Online/Spectator/OnlineSpectatorClient.cs
+++ b/osu.Game/Online/Spectator/OnlineSpectatorClient.cs
@@ -57,14 +57,14 @@ namespace osu.Game.Online.Spectator
             return connection.SendAsync(nameof(ISpectatorServer.BeginPlaySession), state);
         }
 
-        protected override Task SendFramesInternal(FrameDataBundle data)
+        protected override Task SendFramesInternal(FrameDataBundle bundle)
         {
             if (!IsConnected.Value)
                 return Task.CompletedTask;
 
             Debug.Assert(connection != null);
 
-            return connection.SendAsync(nameof(ISpectatorServer.SendFrameData), data);
+            return connection.SendAsync(nameof(ISpectatorServer.SendFrameData), bundle);
         }
 
         protected override Task EndPlayingInternal(SpectatorState state)
diff --git a/osu.Game/Online/Spectator/SpectatorClient.cs b/osu.Game/Online/Spectator/SpectatorClient.cs
index a54ea0d9ee..8f22078010 100644
--- a/osu.Game/Online/Spectator/SpectatorClient.cs
+++ b/osu.Game/Online/Spectator/SpectatorClient.cs
@@ -12,6 +12,7 @@ using osu.Framework.Allocation;
 using osu.Framework.Bindables;
 using osu.Framework.Development;
 using osu.Framework.Graphics;
+using osu.Framework.Logging;
 using osu.Game.Beatmaps;
 using osu.Game.Online.API;
 using osu.Game.Replays.Legacy;
@@ -45,18 +46,6 @@ namespace osu.Game.Online.Spectator
         /// </summary>
         public IBindableList<int> PlayingUsers => playingUsers;
 
-        /// <summary>
-        /// All users currently being watched.
-        /// </summary>
-        private readonly List<int> watchedUsers = new List<int>();
-
-        private readonly BindableDictionary<int, SpectatorState> watchedUserStates = new BindableDictionary<int, SpectatorState>();
-        private readonly BindableList<int> playingUsers = new BindableList<int>();
-        private readonly SpectatorState currentState = new SpectatorState();
-
-        private IBeatmap? currentBeatmap;
-        private Score? currentScore;
-
         /// <summary>
         /// Whether the local user is playing.
         /// </summary>
@@ -77,6 +66,28 @@ namespace osu.Game.Online.Spectator
         /// </summary>
         public event Action<int, SpectatorState>? OnUserFinishedPlaying;
 
+        /// <summary>
+        /// All users currently being watched.
+        /// </summary>
+        private readonly List<int> watchedUsers = new List<int>();
+
+        private readonly BindableDictionary<int, SpectatorState> watchedUserStates = new BindableDictionary<int, SpectatorState>();
+        private readonly BindableList<int> playingUsers = new BindableList<int>();
+        private readonly SpectatorState currentState = new SpectatorState();
+
+        private IBeatmap? currentBeatmap;
+        private Score? currentScore;
+
+        private readonly Queue<FrameDataBundle> pendingFrameBundles = new Queue<FrameDataBundle>();
+
+        private readonly Queue<LegacyReplayFrame> pendingFrames = new Queue<LegacyReplayFrame>();
+
+        private double lastPurgeTime;
+
+        private Task? lastSend;
+
+        private const int max_pending_frames = 30;
+
         [BackgroundDependencyLoader]
         private void load()
         {
@@ -94,6 +105,7 @@ namespace osu.Game.Online.Spectator
 
                     // re-send state in case it wasn't received
                     if (IsPlaying)
+                        // TODO: this is likely sent out of order after a reconnect scenario. needs further consideration.
                         BeginPlayingInternal(currentState);
                 }
                 else
@@ -168,7 +180,20 @@ namespace osu.Game.Online.Spectator
             });
         }
 
-        public void SendFrames(FrameDataBundle data) => lastSend = SendFramesInternal(data);
+        public void HandleFrame(ReplayFrame frame) => Schedule(() =>
+        {
+            if (!IsPlaying)
+            {
+                Logger.Log($"Frames arrived at {nameof(SpectatorClient)} outside of gameplay scope and will be ignored.");
+                return;
+            }
+
+            if (frame is IConvertibleReplayFrame convertible)
+                pendingFrames.Enqueue(convertible.ToLegacy(currentBeatmap));
+
+            if (pendingFrames.Count > max_pending_frames)
+                purgePendingFrames();
+        });
 
         public void EndPlaying(GameplayState state)
         {
@@ -180,7 +205,7 @@ namespace osu.Game.Online.Spectator
                     return;
 
                 if (pendingFrames.Count > 0)
-                    purgePendingFrames(true);
+                    purgePendingFrames();
 
                 IsPlaying = false;
                 currentBeatmap = null;
@@ -222,7 +247,7 @@ namespace osu.Game.Online.Spectator
 
         protected abstract Task BeginPlayingInternal(SpectatorState state);
 
-        protected abstract Task SendFramesInternal(FrameDataBundle data);
+        protected abstract Task SendFramesInternal(FrameDataBundle bundle);
 
         protected abstract Task EndPlayingInternal(SpectatorState state);
 
@@ -230,53 +255,57 @@ namespace osu.Game.Online.Spectator
 
         protected abstract Task StopWatchingUserInternal(int userId);
 
-        private readonly Queue<LegacyReplayFrame> pendingFrames = new Queue<LegacyReplayFrame>();
-
-        private double lastSendTime;
-
-        private Task? lastSend;
-
-        private const int max_pending_frames = 30;
-
         protected override void Update()
         {
             base.Update();
 
-            if (pendingFrames.Count > 0 && Time.Current - lastSendTime > TIME_BETWEEN_SENDS)
+            if (pendingFrames.Count > 0 && Time.Current - lastPurgeTime > TIME_BETWEEN_SENDS)
                 purgePendingFrames();
         }
 
-        public void HandleFrame(ReplayFrame frame)
+        private void purgePendingFrames()
         {
-            Debug.Assert(ThreadSafety.IsUpdateThread);
-
-            if (!IsPlaying)
-                return;
-
-            if (frame is IConvertibleReplayFrame convertible)
-                pendingFrames.Enqueue(convertible.ToLegacy(currentBeatmap));
-
-            if (pendingFrames.Count > max_pending_frames)
-                purgePendingFrames();
-        }
-
-        private void purgePendingFrames(bool force = false)
-        {
-            if (lastSend?.IsCompleted == false && !force)
-                return;
-
             if (pendingFrames.Count == 0)
                 return;
 
-            var frames = pendingFrames.ToArray();
-
-            pendingFrames.Clear();
-
             Debug.Assert(currentScore != null);
 
-            SendFrames(new FrameDataBundle(currentScore.ScoreInfo, frames));
+            var frames = pendingFrames.ToArray();
+            var bundle = new FrameDataBundle(currentScore.ScoreInfo, frames);
 
-            lastSendTime = Time.Current;
+            pendingFrames.Clear();
+            lastPurgeTime = Time.Current;
+
+            pendingFrameBundles.Enqueue(bundle);
+
+            sendNextBundleIfRequired();
+        }
+
+        private void sendNextBundleIfRequired()
+        {
+            Debug.Assert(ThreadSafety.IsUpdateThread);
+
+            if (lastSend?.IsCompleted == false)
+                return;
+
+            if (!pendingFrameBundles.TryPeek(out var bundle))
+                return;
+
+            TaskCompletionSource<bool> tcs = new TaskCompletionSource<bool>();
+
+            lastSend = tcs.Task;
+
+            SendFramesInternal(bundle).ContinueWith(t => Schedule(() =>
+            {
+                bool wasSuccessful = t.Exception == null;
+
+                // If the last bundle send wasn't successful, try again without dequeuing.
+                if (wasSuccessful)
+                    pendingFrameBundles.Dequeue();
+
+                tcs.SetResult(wasSuccessful);
+                sendNextBundleIfRequired();
+            }));
         }
     }
 }
diff --git a/osu.Game/Tests/Visual/Spectator/TestSpectatorClient.cs b/osu.Game/Tests/Visual/Spectator/TestSpectatorClient.cs
index 1322a99ea7..f5da95bd7b 100644
--- a/osu.Game/Tests/Visual/Spectator/TestSpectatorClient.cs
+++ b/osu.Game/Tests/Visual/Spectator/TestSpectatorClient.cs
@@ -21,10 +21,17 @@ namespace osu.Game.Tests.Visual.Spectator
     public class TestSpectatorClient : SpectatorClient
     {
         /// <summary>
-        /// Maximum number of frames sent per bundle via <see cref="SendFrames"/>.
+        /// Maximum number of frames sent per bundle via <see cref="SendFramesFromUser"/>.
         /// </summary>
         public const int FRAME_BUNDLE_SIZE = 10;
 
+        /// <summary>
+        /// Whether to force send operations to fail (simulating a network issue).
+        /// </summary>
+        public bool ShouldFailSendingFrames { get; set; }
+
+        public int FrameSendAttempts { get; private set; }
+
         public override IBindable<bool> IsConnected { get; } = new Bindable<bool>(true);
 
         public IReadOnlyDictionary<int, ReplayFrame> LastReceivedUserFrames => lastReceivedUserFrames;
@@ -47,7 +54,7 @@ namespace osu.Game.Tests.Visual.Spectator
         /// </summary>
         /// <param name="userId">The user to start play for.</param>
         /// <param name="beatmapId">The playing beatmap id.</param>
-        public void StartPlay(int userId, int beatmapId)
+        public void SendStartPlay(int userId, int beatmapId)
         {
             userBeatmapDictionary[userId] = beatmapId;
             userNextFrameDictionary[userId] = 0;
@@ -59,7 +66,7 @@ namespace osu.Game.Tests.Visual.Spectator
         /// </summary>
         /// <param name="userId">The user to end play for.</param>
         /// <param name="state">The spectator state to end play with.</param>
-        public void EndPlay(int userId, SpectatedUserState state = SpectatedUserState.Quit)
+        public void SendEndPlay(int userId, SpectatedUserState state = SpectatedUserState.Quit)
         {
             if (!userBeatmapDictionary.ContainsKey(userId))
                 return;
@@ -74,14 +81,14 @@ namespace osu.Game.Tests.Visual.Spectator
             userBeatmapDictionary.Remove(userId);
         }
 
-        public new void Schedule(Action action) => base.Schedule(action);
-
         /// <summary>
         /// Sends frames for an arbitrary user, in bundles containing 10 frames each.
+        /// This bypasses the standard queueing mechanism completely and should only be used to test cases where multiple users need to be sending data.
+        /// Importantly, <see cref="ShouldFailSendingFrames"/> will have no effect.
         /// </summary>
         /// <param name="userId">The user to send frames for.</param>
         /// <param name="count">The total number of frames to send.</param>
-        public void SendFrames(int userId, int count)
+        public void SendFramesFromUser(int userId, int count)
         {
             var frames = new List<LegacyReplayFrame>();
 
@@ -123,7 +130,15 @@ namespace osu.Game.Tests.Visual.Spectator
             return ((ISpectatorClient)this).UserBeganPlaying(api.LocalUser.Value.Id, state);
         }
 
-        protected override Task SendFramesInternal(FrameDataBundle data) => ((ISpectatorClient)this).UserSentFrames(api.LocalUser.Value.Id, data);
+        protected override Task SendFramesInternal(FrameDataBundle bundle)
+        {
+            FrameSendAttempts++;
+
+            if (ShouldFailSendingFrames)
+                return Task.FromException(new InvalidOperationException());
+
+            return ((ISpectatorClient)this).UserSentFrames(api.LocalUser.Value.Id, bundle);
+        }
 
         protected override Task EndPlayingInternal(SpectatorState state) => ((ISpectatorClient)this).UserFinishedPlaying(api.LocalUser.Value.Id, state);