Ozil was one of many members of the Germany squad who underperformed in Russia, with the defending champions being eliminated during the group stages.
The Arsenal playmaker came in for criticism both during and after the tournament, and Wenger has acknowledged that the 29-year-old did not play to the best of his ability.
Wenger told beIN Sports: "When I watched him play, I could feel there were situations in the game where he could have moved forward, progressed and played more vertical.
"He played security. I was thinking come on, that is not the real Ozil I know, the guy who can kill. He played alright, but he didn't play with complete freedom and played with the handbrake on this World Cup for Germany."
Germany recorded one win and two defeats - to Mexico and Sweden - in their three outings.