The Welshman scored 16 goals for the Gunners last season and struck the winner in the FA Cup final.
His impressive form has raised expectations at the Emirates and Wenger believes that he has struggled under the pressure.
"He is back now," Wenger told Arsenal's official website. "He had a little moment when he was not at his best but that can happen. I am fully confident that he is back.
"He always wants to play. He has a terrific engine and on the pitch he never hides, so when he sometimes makes a mistake it is [noticeable] - but if you look at his overall contribution to the team, it is always fantastic.
"Yes sometimes [he may have been trying too hard]. I believe he felt a bit more pressure to score. You always have to come back to basics. What is my job? Midfielder, win the ball and give a good pass."
Arsenal face North London rivals Tottenham Hotspur in the Premier League tomorrow evening.