Arsene Wenger started his 21st year as Arsenal manager with a controversial 1-0 victory over Burnley at Turf Moor following a 93rd-minute Laurent Koscielny winner.
Defender Koscielny bundled the ball home at the far post from a corner in the third minute of stoppage time, but it looked like his initial shot, which was directed over the bar, came off the his own arm before crossing the line.
Burnley were furious, but referee Craig Pawson allowed the goal, handing Arsenal a vital three points following a stubborn Burnley display.
Alexis Sanchez went closest for the visitors in a game lacking in chances, forcing a good save out of Tom Heaton before volleying just wide from a corner in the second half, while Michael Keane hit the woodwork for Burnley from a header.
The result means Arsenal go up to third, two points off leaders Manchester City, while Burnley sit 14th with seven points.
Petr Cech came back into Wenger's starting XI for David Ospina in the only change for either side, but Arsenal's outfield players struggled to break down Burnley in the first half.
Sanchez's effort from the right of the area deflected off Alex Iwobi and dropped just wide of the post in what was Arsenal's only half chance of the opening 45 minutes.
At the other end, Sam Vokes beat Arsenal's offside trap from Matthew Lowton's curled ball, but the striker should have done better as his unmarked header went half a yard wide of Cech's left-hand post.
Sanchez came close again early in the second half, forcing a good low save out of Tom Heaton at the near post having turned after some pinball inside Burnley's area.
Burnley had their fair share of chances in the second period, Cech beating away Johann Berg Gudmundsson's header, before Keane's towering header from a corner came off the bar and clear.
Sanchez hit a volley just wide late on as the ball dropped down from a corner, and with Arsenal still knocking on the door in final moments, they grabbed the winner in the third minute of two added on at Turf Moor.
As the visitors took a short corner, Sanchez's eventual cross was flicked on by Theo Walcott, with Alex Oxlade-Chamberlain and Koscielny unmarked at the far post to tap home.
Oxlade-Chamberlain stretched for it, but Koscielny got the touch with his right foot, only for the ball to eventually come off his wrist and past Heaton.
With the initial effort heading over the bar, Burnley were right to feel aggrieved, but the all-important three points went to Arsenal.
Player ratings
Burnley: Heaton (6), Lowton (6), Keane (8), Mee (7), Ward (7), Boyd (7), Defour (5), Hendrick (6), Marney (7), Gudmundsson (6), Vokes (6)
Subs used: Arfield (6)
Arsenal: Cech (6), Bellerin (6), Mustafi (6), Koscielny (6), Monreal (5), Cazorla (5), Xhaka (5), Walcott (5), Ozil (5), Iwobi (6), Alexis (6)
Subs used: Elneny (6), Oxlade-Chamberlain (6)
Man of the match: Michael Keane