Despite going behind, the Gunners marched to a 5-1 win at the Emirates Stadium, with the German netting the equaliser and picking up three assists during the match.
The French boss believes that the 27-year-old's display was one of his best games for the club.
"He had an outstanding game," said Wenger. "He scored a very important goal. He has an unbelievable shot because the keeper had no chance. And he gave of course two great balls as well. What is new for us is that we scored on a corner! It was a bit unusual.
"He had a very strong game at West Ham as well. Certainly today it was his most efficient game because I felt he took responsibility at the moment when we needed him. With a player of his experience you expect him to do that.
"I have plenty of candidates [to play through the centre] but I believe still this is his best position [on the left]."
Arsenal travel to Brighton & Hove Albion in the FA Cup on Saturday.