Unai Emery wants Mesut Ozil to be "demanding" for Arsenal in each match as the coach seeks to revive the fortunes of the mercurial playmaker.

After initially shining brightly in north London following his move from Real Madrid in 2013, Ozil has struggled for consistency in recent seasons.

The 29-year-old German, who retired from international duty after the World Cup amid allegations of discriminatory treatment, has continued to be the subject of intense scrutiny at club level.

Ozil failed to make an impact in the Gunners' 2-0 loss at home to reigning champions Manchester City in the opening round of the Premier League season last weekend.

And Emery, speaking ahead of a London derby at Chelsea on Saturday, emphasised the potential importance of the former Schalke and Werder Bremen player, if he can return to his best.

"The positioning, Ozil is playing all his career like a 10 player or like a right winger going inside to receive the ball," he said. 

"It's clear he needs the ball more to give more options in the attacking moments. He needs to do [it] in each match, be demanding for us."

Discussing Ozil's work-rate off the ball, Emery said: "Defensive moments are for each and every player. Don't change Mesut Ozil in his positioning. 

"Every player needs to do [defensive work] in the true moment of a match. There are defensive moments and attacking moments. Every player each needs this commitment.

"For me, we need to start together, whether we are attacking or defending. I want that from every player."