The Reds needed to beat the Gunners after Roberto Mancini's men recorded a dramatic 3-2 win over Tottenham, prior to kick-off at the Emirates Stadium.
United started brightly and took a first-half lead through Antonio Valencia, who calmly latched onto Ryan Giggs’ curled cross to head in at the far post. The only sour note was an early injury to Phil Jones.
Arsenal improved after the break and equalised on 71 minutes thanks to Robin van Persie's neat finish.
Sir Alex's men kept up the pressure though and notched a deserved winner some ten minutes later as Welbeck converted following some excellent work from Valencia and Park.
To help retell the story, we’ve compiled a gallery of the best images from Sunday’s epic encounter.