The England international opened the scoring and then set up a second goal for Olivier Giroud less than a minute later as the London club won 2-1 at Villa Park to go back to the top of the Premier League.
Wilshere struggled with injury earlier this season and then a loss of form led to Wenger omitting him from Arsenal's line-up.
But the 22-year-old showed his class in the victory at Villa and Wenger points to Wilshere's fitness levels as being the key to his return to form.
"Jack has found his change of pace back and his penetration." said the Arsenal manager.
"His game is about that. He's not only a passer, he's a guy who's incisive with the ball.
"That's his strength and for that you need to be at the top of your game physically. You can see it when he's training well physically. He's coming back to his best."
Arsenal are waiting to discover the extent of injuries suffered by Tomas Rosicky (nose) and Nacho Monreal (metatarsal) at Villa Park.
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