Former Arsenal goalkeeper Jens Lehmann has warned his compatriot Mesut Ozil he must start performing in the big games for Arsene Wenger’s side this season. The retired stopper is a huge fan of the German playmaker, but feels he needs to deliver world-class displays on a more regular basis in north London. Ozil remains highly regarded in football circles and is a popular figure amongst Gunners supporters. However, some critics say he’s failed to justify the £42m fee paid to Real Madrid in the summer of 2013. Lehmann doesn’t necessarily agree with those accusations but is adamant that by adding more consistency to his game the 26-year-old playmaker will quieten his detractors and cement his status as a star player at the Emirates.