Topics: Danny Wellbeck, Arsenal, FA Cup, Louis van Gaal, Arsene Wenger
It was Wellbeck's eighth goal in any competition for Arsenal. He started playing for Manchester United since he was eight.

Out of the 11 players on the field for Arsenal's, it was a former Red Devil who knocked his previous team out of the FA Cup. Danny Welbeck’s goal in the second half closed the door Manchester United’s attempt to make it to Wembley.

The 24-year-old did celebrate his goal at Old Trafford, but recognized there were mixed emotions involved. The goal gave Arsenal its first win (2-1) at the Theatre of Dreams since 2006.

WATCH: Welbeck score and celebrate his goal for Arsenal

“Manchester United is a club that means so much to me,” Wellbeck claimed. “I’m a fan and it’s hard to knock them out.”

Welbeck had joined Man United when he was only eight. After 16 years with the club, Louis van Gaal set him free to bring Radamel Falcao. After what happened on Monday night, that is considered the Dutchman’s biggest mistake.

When van Gaal was questioned after the game about that same decision, he stood firmly by what he believed was right last August. Even if Falcao saw the entire game unfold from the bench.

“A lot of times a player shall be very motivated against the club he played for, but I think we gave that goal away,” the Red Devils manager said.

Van Gaal and Man United said goodbye to the FA Cup due to Welbeck's goalVan Gaal still stands by his decision to let Welbeck leaveArsene Wenger was pleased with the mentality of his players throughout the match. He praised Welbeck on how well he played at his old stomping ground.

“He focused just on his game and played football the way he wanted to,” Le Professeur said.

Arsenal fans had fun with the situation on Twitter