Charlie Austin looked to have earned a hard-fought point when he equalised (73) with only his second touch from the bench, but Welbeck scored his second of the game just eight minutes later and the header proved decisive.
However, after Shane Long's opener, Pierre-Emerick Aubameyang pulled one back before Danny Welbeck gave Arsenal the lead.
Danny Welbeck scored twice as Arsenal came from behind to beat Southampton 3-2 at the Emirates this afternoon.
Despite some lacklustre attacking in the first half, Southampton returned after the break transformed, pressing forward and keeping real pressure on Arsenal.More news: Israeli police: Palestinian who tried to stab Israeli shot
Elneny then got himself sent off as he shoved Cedric in the back ahead of the final whistle to end a fascinating and feisty encounter at the Emirates.
The game ended in bad-tempered fashion, with Southampton's Jack Stephens and Arsenal's Mohamed Elneny both sent off in the closing stages.
They had been level for eight minutes when Dusan Tadic allowed Alex Iwobi to cross for Welbeck, who had just produced a contender for miss of the season, to rise above Cédric Soares and head home Arsenal's victor.
Southampton was looking for the equalizer after Welbeck grabbed the home side's victor late, minutes after missing an easier chance to score.More news: IPL 2018: KKR to take on RCB in Kolkata Sunday
Danny Welbeck made up for an bad miss just moments earlier, by doubling his goal haul to two, today.
"I thought there'd be another opportunity to get a goal and get the victor".
Don't get me wrong, he wants to win and so do I and sometimes we probably get a little bit silly, but there you go.
But he made no mistake nine minutes from time when he headed Iwobi's delivery to the back post beyond McCarthy. "It just shows the level of competition in the Premier League", he said.More news: Deadly fire in Trump Tower in Manhattan
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