diff --git a/osu.Game/Online/Multiplayer/StatefulMultiplayerClient.cs b/osu.Game/Online/Multiplayer/StatefulMultiplayerClient.cs
index 032493a5c6..f454fe619b 100644
--- a/osu.Game/Online/Multiplayer/StatefulMultiplayerClient.cs
+++ b/osu.Game/Online/Multiplayer/StatefulMultiplayerClient.cs
@@ -4,6 +4,7 @@
 #nullable enable
 
 using System;
+using System.Collections.Generic;
 using System.Diagnostics;
 using System.Linq;
 using System.Threading;