The Germany international has not scored in his last eight Premier League matches, and has failed to record an assist since December.
Ozil was also singled out after the Gunners' 5-1 loss to Liverpool on Saturday, having lost possession softly in the build-up to two of the Reds' quick-fire goals during a devastating 20-minute salvo.
|15/2||Arsenal are 15/2 with Betway to win the Premier League|
Wenger told reporters: "He works very hard to adapt to the Premier League. For me he's an exceptional player. He was like everybody else on Saturday [in the 5-1 defeat to Liverpool]. He works very hard in training to improve."
Arsenal will need to re-find their defensive solidity to contain a star-studded Manchester United attack on Wednesday night, which contains former north London frontman Robin van Persie, and Wenger is confident the collapse at Anfield was just a blip.
"Van Persie is a great player," the Frenchman continued. "It's down to how well we defend against him tomorrow.
"We've been very stable until now defensively, we have to consider how well we have done until now."
Wenger also confirmed that Arsenal have no new injury problems to contend with after Saturday's match, while Yaya Sanogo is back to full fitness and available to face United.