diff --git a/src/server/scripts/EasternKingdoms/ZulGurub/instance_zulgurub.cpp b/src/server/scripts/EasternKingdoms/ZulGurub/instance_zulgurub.cpp
index f3d16c9f604..05a3a0161fd 100644
--- a/src/server/scripts/EasternKingdoms/ZulGurub/instance_zulgurub.cpp
+++ b/src/server/scripts/EasternKingdoms/ZulGurub/instance_zulgurub.cpp
@@ -65,6 +65,7 @@ class instance_zulgurub : public InstanceMapScript
             void Initialize()
             {
                 _defeatedBossesCount = 0;
+                _killedGurubashiSpiritWarriorMask = 0;
             }
 
             void OnCreatureCreate(Creature* creature) override