diff --git a/binaries/data/mods/public/gui/common/functions_global_object.js b/binaries/data/mods/public/gui/common/functions_global_object.js
index 5291930059..f896ec8a75 100644
--- a/binaries/data/mods/public/gui/common/functions_global_object.js
+++ b/binaries/data/mods/public/gui/common/functions_global_object.js
@@ -31,27 +31,3 @@ function displayGamestateNotifications()
 
 	setTimeout(displayGamestateNotifications, 1000);
 }
-
-/**
- * This function is called from the engine whenever starting a game fails.
- */
-function cancelOnLoadGameError(msg)
-{
-	Engine.EndGame();
-
-	if (Engine.HasXmppClient())
-		Engine.StopXmppClient();
-
-	Engine.SwitchGuiPage("page_pregame.xml");
-
-	if (msg)
-		Engine.OpenChildPage("page_msgbox.xml", {
-			"width": 500,
-			"height": 200,
-			"message": msg,
-			"title": translate("Loading Aborted"),
-			"mode": 2
-		});
-
-	Engine.ResetCursor();
-}
diff --git a/binaries/data/mods/public/gui/loading/loading.js b/binaries/data/mods/public/gui/loading/loading.js
index 80c95e0f91..f3e217b108 100644
--- a/binaries/data/mods/public/gui/loading/loading.js
+++ b/binaries/data/mods/public/gui/loading/loading.js
@@ -1,6 +1,6 @@
 var g_LoadingPage;
 
-function init(data)
+async function init(data)
 {
 	g_LoadingPage = {
 		"initData": data,
@@ -11,14 +11,38 @@ function init(data)
 	};
 
 	Engine.SetCursor("cursor-wait");
-}
 
-/**
- * This is a reserved function name that is executed by the engine when it is ready
- * to start the game (i.e. loading progress has reached 100%).
- */
-function reallyStartGame()
-{
-	Engine.SwitchGuiPage("page_session.xml", g_LoadingPage.initData);
-	Engine.ResetCursor();
+	// reallyStartGame and cancelOnLoadGameError are reserved names that are called by the engine.
+	// reallyStartGame is called when it is ready to start the game (i.e. loading progress has reached
+	// 100%).
+	// cancnelOnLoadGameError is called when there is an error.
+	return new Promise(closePageCallback =>
+	{
+		globalThis.reallyStartGame = () =>
+		{
+			Engine.ResetCursor();
+			closePageCallback({ [Engine.openRequest]: {
+				"page": "page_session.xml",
+				"argument": data
+			} });
+		};
+		globalThis.cancelOnLoadGameError = async() =>
+		{
+			Engine.ResetCursor();
+			Engine.EndGame();
+
+			if (Engine.HasXmppClient())
+				Engine.StopXmppClient();
+
+			await Engine.OpenChildPage("page_msgbox.xml", {
+				"width": 500,
+				"height": 200,
+				"message": errorMessage,
+				"title": translate("Loading Aborted"),
+				"mode": 2
+			});
+
+			closePageCallback({ [Engine.openRequest]: { "page": "page_pregame.xml" } });
+		};
+	});
 }