LONDON - Bafetimbi Gomis scored a late, technology-assisted winner as Swansea City compromised Arsenal's quest for automatic Champions League qualification with a smash-and-grab 1-0 away victory on Monday.
Arsenal had won nine of their previous 10 games, only dropping points in a goalless draw with champions Chelsea, but after being kept at bay by their former goalkeeper Lukasz Fabianski, they were undone in the 85th minute.
Gomis, a 74th-minute replacement for Ki Sung-yueng, sent a header towards goal and although Arsenal goalkeeper David Ospina appeared to have clawed it away, the Goal Decision System showed that the ball had in fact crossed the line.
"We were unlucky against a team who refused to play completely and just defended," complained Arsenal manager Arsene Wenger.
"We rushed our finishing because we had plenty of chances in the second half. It was just a question of scoring a goal." It was Arsenal's first home defeat in the league since November, when they lost 2-1 to Manchester United, two weeks after going down by the same scoreline at Swansea.
United can overtake Arsenal and take possession of third place by beating them at Old Trafford on Sunday, although Wenger's side retain a game in hand at home to relegation-threatened Sunderland.
Garry Monk's Swansea, meanwhile, are now a point off seventh place, which will yield a Europa League spot if Arsenal beat Aston Villa in the FA Cup final on May 30, and two points below sixth-place Tottenham Hotspur.
"Why shouldn't we push for that?" said Monk. "Today showed what we're about and we'll see where the last two games take us.
"We worked all week on our plan. The players were magnificent and carried it out to the letter." With Aaron Ramsey overcoming a knock sustained in last week's 3-1 win at Hull City, Arsenal fielded an unchanged team for the fifth league game running, something that last happened in January 1994.
It was a sign of Wenger's satisfaction with recent performances, but although Arsenal dominated possession in the first half, Swansea's well-organised 4-1-4-1 system kept them at bay.
Ramsey set up Olivier Giroud for an early header that landed on the roof of the net, but Swansea, who deployed Gylfi Sigurdsson as a lone forward, carried menace on the break.