Arsenal legend Jens Lehmann believes Mesut Ozil must start delivering in big games if he is to prove himself at the North London club.
German playmaker Ozil improved his output for the Gunners last season but his compatriot still wants to see him step up when the stakes are high.
"Everyone knows he can be a fantastic player. But you need to be a fantastic player in the big games," Lehmann told The Sun.
"You don't need to be a fantastic player in the small games and mediocre player in the big games.
"He can definitely do that but now he must prove it. You need to know how to think and how to programme yourself.
"Of course he can improve. You can't get better on the day that you retire from football - but you can every day before that."
Ozil has won two FA Cups with the Gunners since arriving at the club from Real Madrid two years ago.