Danny Welbeck's brace secured three points for Arsenal.
Danny Welbeck's late header gave Arsenal a 3-2 victory over relegation-threatened Southampton in the Premier League on Sunday. Charlie Austin came off the bench to equalize for Southampton with his first touch after Shane Long's earlier effort had been cancelled out by goals from Pierre-Emerick Aubameyang and Welbeck.
But Welbeck was on hand to score his second of the game and give Arsenal a third successive league victory.
There was a fiery end to the game which saw both sides finish with 10 men as Jack Stephens and Mohamed Elneny saw red.
Stephens went for pushing Jack Wilshere to the ground, with Elneny dismissed in stoppage time for raising his hands following an altercation with Cedric Soares.
Arsenal remains sixth in the standings, 13 points from Tottenham in the fourth Champions League place with six games remaining. Southampton stayed in the relegation zone with 28 points from 32 matches.
This game was the clearest indication yet that Arsene Wenger is now prioritizing the Europa League — with victory in the competition securing a route into the Champions League.
The Arsenal manager made seven changes from Thursday's win over CSKA Moscow. Wilshere and Mesut Ozil started on the bench and Laurent Koscielny and Aaron Ramsey were rested completely.
Southampton had the best of the early chances, Dusan Tadic drifting in behind before picking out James Ward-Prowse, who could not mark his 200th Southampton appearance with a goal as his effort was cleared off the line by Hector Bellerin.
Mark Hughes saw his side take the lead as Tadic fed Cedric out wide, with the full-back's low cross to the near post left by both Petr Cech and Skhodran Mustafi. That allowed Long to nip in between the pair and sweep home his first goal since Jan. 2 in the 17th minute.
Aubameyang scored for Arsenal after going 1-0 down.
Arsenal was misfiring until Aubameyang started and finished a flowing move in the 28th minute with a deft finish past the onrushing Alex McCarthy following Welbeck's inventive flick. The Gabon striker has now scored six goals in his first eight league games.
The equalizer brought a shift in momentum, and Welbeck failed to make telling contact with Granit Xhaka's corner before Calum Chambers' acrobatic attempt was smothered by McCarthy.
Welbeck put the hosts ahead in the 38th as he collected Alex Iwobi's slide-rule pass before cutting inside and seeing his shot deflect in off the heel of Maya Yoshida. It was the England forward's first league goal since September.
McCarthy had to be alert at the start of the second half to make smart saves from Aubameyang and Xhaka with Iwobi also drawing another stop as Arsenal looked to kill off the game.
Southampton's chances were limited, but Elneny had to be on hand to clear off the line as Wesley Hoedt sent a header toward goal with Cech scrambling to tip Long's header behind soon after.
Long was celebrating a second of the afternoon only to see the goal rightly ruled out for offside as he steered Cedric's drive past Cech.
Saints were starting to come back into the contest and Cech was on hand again to keep out a long-range Hoedt strike as Wenger reacted by introducing Wilshere and Alexandre Lacazette from the bench.
Hughes, meanwhile, turned to Austin and was instantly rewarded as the striker turned home the equalizer in the 73rd with his first touch after strong work from Cedric.
Welbeck passed up a fine chance to put Arsenal back ahead as he turned Wilshere's pull-back high and wide before Austin bustled through at the other end to poke straight at Cech.
Welbeck scored the winner for Arsenal in the 81st minute.
After his great chance moments earlier, Welbeck made amends by heading Arsenal in front for a second time in the 81st, rising highest at the back post to meet Iwobi's cross.
