diff --git a/osu.Game/Screens/Play/SubmittingPlayer.cs b/osu.Game/Screens/Play/SubmittingPlayer.cs
index 83adf1f960..fb3481cbc4 100644
--- a/osu.Game/Screens/Play/SubmittingPlayer.cs
+++ b/osu.Game/Screens/Play/SubmittingPlayer.cs
@@ -41,6 +41,7 @@ namespace osu.Game.Screens.Play
         [Resolved]
         private SessionStatics statics { get; set; }
 
+        private readonly object scoreSubmissionLock = new object();
         private TaskCompletionSource<bool> scoreSubmissionSource;
 
         protected SubmittingPlayer(PlayerConfiguration configuration = null)
@@ -228,16 +229,19 @@ namespace osu.Game.Screens.Play
                 return Task.CompletedTask;
             }
 
-            if (scoreSubmissionSource != null)
-                return scoreSubmissionSource.Task;
+            lock (scoreSubmissionLock)
+            {
+                if (scoreSubmissionSource != null)
+                    return scoreSubmissionSource.Task;
+
+                scoreSubmissionSource = new TaskCompletionSource<bool>();
+            }
 
             // if the user never hit anything, this score should not be counted in any way.
             if (!score.ScoreInfo.Statistics.Any(s => s.Key.IsHit() && s.Value > 0))
                 return Task.CompletedTask;
 
             Logger.Log($"Beginning score submission (token:{token.Value})...");
-
-            scoreSubmissionSource = new TaskCompletionSource<bool>();
             var request = CreateSubmissionRequest(score, token.Value);
 
             request.Success += s =>