Marseille goalkeeper Steve Mandanda believes Mesut Ozil will take Arsenal on to the next level this season.
The Frenchman, whose side face Arsenal at the Stade Velodrome on Wednesday, has warned his Marseille teammates to be wary of the German playmaker.
Mandanda, speaking ahead of his side's Champions League encounter against the Gunners, said of Arsenal's £42.4million recruit from Real Madrid: "Now Ozil has increased Arsenal's level in attack.
"His arrival has taken Arsenal to another level and he is perfect for the style of football and play that Wenger likes. I never expected Real Madrid to allow him to leave."
The 28-year-old has also praised international teammate Olivier Giroud, who has started the season off in fine form by scoring five goals in six games for Arsenal.
"Giroud is in sensational form. We have to stop them from scoring and creating danger but that will not be easy. They look a very strong team," added Mandanda.
As well as facing Arsenal, Marseille will also face tough ties against Napoli and last season's Champions League runners-up Borussia Dortmund.
And Mandanda believes his side have to win their home games if they are going to have any chance of progressing to the last 16 of the Champions League.
He concluded: "This Champions League group is terrific. For any club to progress, every game must be like a final and you have to win your home games. Unless you do that, you have no chance."