Antonio Valencia put the Reds ahead on the stroke of half-time with a fine header from Ryan Giggs' excellent cross.
Robin van Persie equalised for the Gunners on 71 minutes with a low drive into the corner, but United didn't let their heads drop and some inspired play down the right from Valencia allowed Danny Welbeck to blast home the winner from close range nine minutes from time.
MUTV Online is packed with other great content not to be missed, including post-match interviews, Sir Alex Ferguson's weekly press conferences, special one-off video features, Reserves and Academy action and more.
Live radio commentary is also available for every 2011/12 first-team game, followed by video highlights at various embargo times including midnight UK time on matchday for Barclays Premier League games.
*MUTV Online is available to fans worldwide with the exception of Hong Kong (HK), Malaysia (MY), Vietnam, Cambodia and Laos.