diff --git a/data/battle_scripts_1.s b/data/battle_scripts_1.s
index f4ca9abf8b..549a882a0f 100644
--- a/data/battle_scripts_1.s
+++ b/data/battle_scripts_1.s
@@ -368,7 +368,7 @@ gBattleScriptsForMoveEffects:: @ 82D86A8
 	.4byte BattleScript_EffectAttackerDefenseDownHit
 
 BattleScript_EffectAttackerDefenseDownHit:
-	setmoveeffect MOVE_EFFECT_DEF_MINUS_1 | MOVE_EFFECT_AFFECTS_USER
+	setmoveeffect MOVE_EFFECT_DEF_MINUS_1 | MOVE_EFFECT_AFFECTS_USER | MOVE_EFFECT_CERTAIN
 	goto BattleScript_EffectHit
 
 BattleScript_EffectSleepHit:
@@ -7950,4 +7950,3 @@ BattleScript_JabocaRowapBerryActivate_Dmg:
 	call BattleScript_HurtAttacker
 	removeitem BS_TARGET
 	return
-