Wilshere had to field plenty of remarks from Tottenham fans during their win over Aston Villa on Monday night and Wilshere responded by pledging £3,000 to charity if Spurs finish above their local rivals this season.
The England international had one condition - that Spurs fans donate to charity if Arsenal are the top north London club.
"Jack made a contest," Wenger told arsenal.com. "The good thing about that is that a charity will get some money.
"He said that the supporters of Tottenham will have to pay £1 each, so because they have many I hope the charity will get a lot of money and Wilshere will not have to pay anything.
"[The challenge shows] that we are ready for a challenge and the charity will get some money."