Arsenal midfielder Mesut Ozil is a fantastic player but has to be more consistent in big games, Jens Lehmann has declared.
Tormented by injuries, the Germany international was overshadowed by Alexis Sanchez and Santi Cazorla last season at Arsenal as he struggled to make the same impact as his team-mates in midfield.
And Lehmann believes he must step up against the top teams in the Premier League and Champions League.
"Everyone knows he can be a fantastic player," Lehmann told The Sun.
"But you need to be a fantastic player in the big games.
"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."