The Dane was replaced by Eduardo midway through the first half and Gunners boss Arsene Wenger confirmed that the problem is serious.

"He's got a groin problem, it's quite serious and he could be out four weeks at least," Wenger said after the game.

Commenting on the derby win, Wenger believes that his side have what it takes to win their first Premiership title in six years.

"Do we have enough? I say yes. I've said that since the first day of the season and it won't change now," added the Frenchman.

"We want to show consistency and intelligence and that is not easy. I believe we have the opportunity and it will be down to our attitude.

"I am positive for us because we have the minimum points with the performances we have produced."