Welbeck scored what proved to be the winner in tonight’s FA Cup quarter-final tie against his former club Manchester United at Old Trafford.
The 24-year-old striker found the target just past hour mark, when he drove the ball home from close range after getting past United goalkeeper David de Gea.
It was Welbeck’s first game against the Red Devils at Old Trafford since leaving them in the summer of 2014.
Although the England international celebrated his strike on the pitch (click here to read more), he is not too fussed about it in the dressing room.
"Danny Welbeck was a great player here at United, he's a bit quiet in the dressing room at the moment,” Mertesacker told BBC Sport.
“I think it hurts him a bit as well as he was here for a long time. We tried to get him going and to tell him he can enjoy special moments with Arsenal."
Welbeck rose through the ranks at United and was on their books until the summer of 2014, when manager Louis van Gaal deemed him surplus to requirements.
The Dutchman later claimed that the striker did not have the quality to start regularly for his team, as reported by The Telegraph.
While Welbeck has not been in great form so far this season, he has scored the winner that has ended all realistic chances of United winning silverware this campaign.