Robin van Persie condemned Chelsea to their second defeat of the season after Arsenal fought back from a goal down to seal a 2-1 win at Stamford Bridge.
Johan Djorou put Jose Bosingwa's cross through his own net on 31 minutes before van Persie struck twice in three minutes either side of the hour mark to give Arsene Wenger's men victory.
The result sees the Gunners move to within two points of third-placed United, who are five points behind Chelsea and Liverpool (who entertain West Ham on Monday night) with a game in hand.
Elsewhere on Sunday, a Steven Pienaar goal was enough to give Everton a 1-0 victory at Tottenham, while Sean Davis' late strike gave Portsmouth a 3-2