How the game went
A Kieran Gibbs own-goal and a late effort from skipper Wayne Rooney handed Manchester United their first victory on the road in over seven months, with Arsenal managing only a consolation goal through substitute Olivier Giroud.
United enter the top four of the Premier League following their maiden three-point haul away from Old Trafford.
Former Red Devil Danny Welbeck missed a couple of decent chances to make manager Louis van Gaal eat his words, after the Dutchman sold the Manchester-born forward to the Gunners over the summer.
Jack Wilshere should have scored before he was lucky to not see a red card having shoved his head into Marouane Fellaini's chest, but United held on until Gibbs turned Antonio Valencia's low cross past his own goalkeeper.
Rooney doubled United's lead as he and Angel di Maria hit Arsenal on the counter-attack and, although di Maria was guilty of missing a great chance to add a third, the returning Giroud's strike could not spark a late revival for the hosts.