Arsenal came from behind to beat Swansea City 2-1 in the Premier League on Saturday as second-half goals from Sead Kolasinac and Aaron Ramsey saw off the injury-weakened visitors.
Victory for the Gunners in Arsene Wenger's 800th Premier League match in charge means champions Chelsea, who play in the day's late kick-off at Bournemouth, must win to retake fourth spot in the table. Swansea, meanwhile, sank to 17th place, just above the relegation zone.
The visitors, without injured striker Wilfried Bony, midfielder Renato Sanches and defender Martin Olsson, took the lead in the 22nd minute against the run of play. Sam Clucas ran on to a pass from Tammy Abraham and slotted the ball neatly beneath Arsenal goalkeeper Petr Cech.
Arsenal's powerful Bosnian left back Kolasinac equalised in the 51st minute and set up Ramsey to put the home side ahead in the 58th with his third goal of the season.
Arsenal manager Wenger praised Kolasinac, who joined the club on a free transfer from Germany's Schalke this year, for putting the home side back in control of the game.
"Kolasinac was decisive today," he told reporters. "Since he has arrived he has convinced everybody that he is a good signing, and overall when you see the quality of his performance again today, you see there are still some good deals to make out there."
Kolasinac came off with a slight hip injury in the 78th minute, but Wenger is hoping he will be able travel with the squad to league leaders Manchester City.
"We hope to get him fit for next Sunday. He had that before, and we managed to get him always available," Wenger said.
Swansea coach Paul Clement was keen to take away positives from the game, picking out the creative play of Abraham that led to the opening goal.
"We were always in the game, right up until the last moments. When you've got someone like him (Abraham) you believe you can get another chance," he said.
"Unfortunately, we didn't get that opportunity at the end," he said.
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