His goal against Crystal Palace was his eighth of the season.
"Olivier always puts a shift in, that is what makes him great," said Wenger. "He misses some chances but he always gets the support from our fans because he shows he is ready for a fight.
"The fact that he kept going against Palace got him the goal.
"How much he has improved, I don't know. But he has, that's obvious to everybody. If he keeps working like that then he will improve again. I like his spirit."
For the big stories and the banter follow us on Twitter: @tribalfootball