The Frenchman described the 21-year-old as a "complete" midfielder and insisted that he is back to his best after an long injury layoff.
"What is pleasing is that he's ahead of schedule. Jack is completely back to his best and I would never have believed that would have happened as soon as January," Sky Sports News quotes Wenger as saying.
"He can play everywhere - he can defend and attack. He has got back his burst with the ball so I used him closer to the strikers and he was always dangerous.
"A complete midfielder can defend and attack and Jack can also dribble and give a final ball so the closer players like him are to the goal the better it is for them."
The Gunners dominated the third-round replay but it took them until the 86th minute to secure passage into the next phase, when Wilshere found the bottom corner from the edge of the box.