Arsene Wenger has praised Danny Welbeck's "mental strength" after the striker scored the winning goal against his former club.

Nacho Monreal opened the scoring before Wayne Rooney equalised four minutes later, but Welbeck scored with 30 minutes remaining to send Arsenal through to the FA Cup semi-final.

Welbeck signed for the Gunners from Manchester United in September for a fee of £16m.

"We want all to do well when we play against our former club, to show we are a great player, but it's not easy to deal with the mental situation," Wenger told Sky Sports News.

"He focused just on his game and didn't do anything special, just played football like you want him to play, and I think he has shown mental strength."

Arsenal will play Bradford City or Reading in the semi-final.