It was a day never to forget for Manchester United in North London on Sunday as three goals in the opening 20 minutes sealed a 3-0 win for Arsenal.
The hosts raced in a two-goal lead through Alexis Sanchez and Mesut Ozil in the first 10 minutes, before Sanchez netted another soon after.
Having been outplayed for most of the first period, United improved after the break and forced Petr Cech into a couple of good stops, but the damage had already been done.
Louis van Gaal made two changes to the side that came from behind to beat Wolfsburg, with Michael Carrick and Ashley Young coming in for Morgan Schneiderlin and Antonio Valencia. Young came on at right full-back in midweek, but having impressed so much down the left last term, as a winger and wing-back, he returned to a more familiar role, with Matteo Darmian, a starter at left-back for the last two games, back in the right-back slot.