Manchester United's £82m new boy Antony scored on his debut and Marcus Rashford got two as Erik ten Hag's men ended Arsenal's 100% start to the season at Old Trafford.
The Brazilian opened the scoring 10 minutes before half-time in the pulsating duel, sweeping a shot into the far corner.
Rashford claimed the assist for that and then, after Bukayo Saka had levelled on the hour, the England striker profited from two clinical United counter-attacks.
Bruno Fernandes was at the heart of both, splitting the Arsenal defence for Rashford's first, then sending Christian Eriksen clear as the Dane provided the striker with a tap-in.