diff --git a/src/d_main.c b/src/d_main.c
index 7cbddf194..2f75bb5a9 100644
--- a/src/d_main.c
+++ b/src/d_main.c
@@ -1828,23 +1828,32 @@ void D_SRB2Main(void)
 					newskill = (INT16)j;
 			}
 
-			if (grandprixinfo.gp == true)
+			// Invalidate if locked.
+			if ((newskill >= KARTSPEED_HARD && !M_SecretUnlocked(SECRET_HARDSPEED, true))
+				|| (newskill >= KARTGP_MASTER && !M_SecretUnlocked(SECRET_MASTERMODE, true)))
 			{
-				if (newskill == KARTGP_MASTER)
-				{
-					grandprixinfo.masterbots = true;
-					newskill = KARTSPEED_HARD;
-				}
-
-				grandprixinfo.gamespeed = newskill;
-			}
-			else if (newskill == KARTGP_MASTER)
-			{
-				newskill = KARTSPEED_HARD;
+				newskill = -1;
 			}
 
 			if (newskill != -1)
+			{
+				if (grandprixinfo.gp == true)
+				{
+					if (newskill == KARTGP_MASTER)
+					{
+						grandprixinfo.masterbots = true;
+						newskill = KARTSPEED_HARD;
+					}
+
+					grandprixinfo.gamespeed = newskill;
+				}
+				else if (newskill == KARTGP_MASTER)
+				{
+					newskill = KARTSPEED_HARD;
+				}
+
 				CV_SetValue(&cv_kartspeed, newskill);
+			}
 		}
 
 		if (server && (dedicated || !M_CheckParm("+map")))