Arsenal slumped to a last-gasp 2-1 Premier League defeat at relegation-threatened Brighton & Hove Albion on Saturday in a blow to the London club's chances of securing European football next season.
Frenchman Neal Maupay struck the winner five minutes into stoppage time after Nicolas Pepe's delightful second-half opener had been cancelled out by Lewis Dunk.
The defeat left the Gunners, who lost keeper Bernd Leno to injury in the first half, in ninth place with 40 points from 30 games, six behind fifth-placed Manchester United.
The result came three days after Mikel Arteta's side suffered a 3-0 rout at Manchester City as the Premier League returned after a three-month hiatus due to the coronavirus health crisis.
Brighton are 15th on 32 points, five points above third-from-bottom Bournemouth, who have a game in hand.
Arsenal had four attempts in the opening 10 minutes - more than in the entire game against Manchester City - but they still could not find the net.
Their best chance came in the 31st minute when Alexandre Lacazette's header was tipped away by Mathew Ryan after the Frenchman had been set up by Bukayo Saka, Arsenal's most dangerous player who struck the bar in the eighth minute.
Leno was carried off the pitch on a stretcher in the 40th minute with a possible knee injury after a tussle with Maupay.
He was replaced by Emiliano Martinez, who made his first Premier League appearance since 2017 and was tested right away by Aaron Mooy.
Pepe broke the deadlock in the 68th with a splendid curled effort into the far top corner.
It took Brighton seven minutes to level, with Dunk forcing the ball in after Maupay's header had been blocked on the line by Rob Holding following a corner.
Five minutes into stoppage time, substitute Alexis Mac Allister played the ball forward and Maupay collected it after letting it run through his legs and flicked it past the keeper to inflict a second consecutive defeat on Arsenal.