The Arsenal boss believes confidence has been restored in the France international following his sublime strike during the midweek victory against West Ham United.
And now Wenger has called on the 27-year-old to start delivering more goals with his head as the Gunners look to secure UEFA Champions League football for next season - starting with three points at Hull City on Sunday.
"The quality of the goal gives him, I think, confidence again, gives him credibility again for people who questioned his ability, so that is important," Wenger said.
"He has done well. He has gone, like Mesut Ozil, through a more difficult period recently.
"He is a strong lad, strong mentality, strong positive guy. He has a great mentality that's what I think got him back.
"He has scored 20 goals that is a great record and he is working very hard for the team.
"Maybe he has improved his finishing but there is still some room for improvement.
"For example you expect him to score more headers."