Having put CSKA Moscow to the sword on Thursday, winning the first leg of the Europa League quarter-final 4-1, Arsenal made heavy weather of seeing off a side sitting in the Premier League's relegation zone.
Welbeck made it 2-1 in the 38th, leaving McCarthy helpless with a deflected shot from an Alex Iwobi feed.
An equaliser was coming, though, and was netted by substitute Austin the 73rd minute after Cedric had burst into the box to square the ball for a tap in.
Southampton's Jack Stephens and Mohamed Elneny of Arsenal both saw red in stoppage time for violent conduct, leaving their respective sides to play out the closing minutes with 10 men.
Southampton remains three points back of safety.
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Park was also convicted of passing on presidential documents with sensitive information to Choi via one of her presidential aides. When the wide-ranging corruption scandal broke previous year it prompted massive street protests against Park across the country.
But Southampton couldn't hold on, Welbeck's second of the day - a header from close range - securing all three points for the Gunners.
Welbeck narrowly failed to get on the end of a Wilshere cross after he hooked the ball back from the byline on 79 minutes. I know when I get the opportunity in front of goal I will put them away.
Aubameyang will be looking to continue the fine form in front of goal when Arsenal play host to Southampton in their next league game on Sunday.
This isn't the first time that Long has gotten on the score-sheet against Arsenal.
Danny Welbeck both scored and assisted in a Premier League match for the first time since September (against Bournemouth), which was also the last time he netted a league goal.
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- In fact, only Wayne Rooney (7) and Robin Van Persie (6) have scored more Premier League goals against Petr Cech than Shane Long (5).
Arsenal play again on Thursday, against CSKA Moscow in Russian Federation, and their next Premier League game is against Newcastle on April 15th.
"Clearly we've got talented players - you've seen that today - we just need that element of determination and ability to affect the opposition when the going gets tough".
And Aubameyang's goal versus Southampton meant the striker has been directly involved in seven goals (six goals, one assist) in his opening seven matches. Long almost scored another, but he was flagged for offsides.
Saints were starting to come back into the contest and Cech was on hand again to keep out a long-range Hoedt strike as Gunners boss Wenger reacted by introducing Wilshere and Alexandre Lacazette from the bench.
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Guardiola's ire was aimed exclusively at Raiola, with whom he has had a long-running feud dating back to his Barcelona days. His team still has more chances to clinch the league, but only 90 minutes to salvage its Champions League dream.