A Danny Welbeck double prevented Southampton from moving out of the Premier League's bottom three on Sunday afternoon.
An unconvincing Arsenal performance saw them edge past the relegation candidates, with Welbeck's brace and a goal from Pierre-Emerick Aubameyang cancelling out strikes from Shane Long and Charlie Austin.
Signs of improvement from Saints
Southampton were far more positive than they had been in their 3-0 drubbing at West Ham United the previous week, with the midfield advancing forward to support lone forward Long - who chased and harried Arsenal's defenders, hoping to force an error.
They almost led when James Ward-Prowse diverted an early effort goalwards, only for it to be cleared off the line by Calum Chambers, and they were eventually the beneficiaries of notoriously poor Arsenal defending when miscommunication from Petr Cech and Shkodran Mustafi allowed Long to flick Cedric Soares' cross across Cech and into the corner. It was only the second goal in 48 appearances for the Irishman, whose lack of goals has somewhat epitomised his side's season.
The Saints were momentarily outside the relegation zone, ahead of Crystal Palace on goal difference, but their own defensive deficiencies cost them their surprise lead as they conceded twice in nine minutes. The first goal came on 29 minutes when a wonderful free-flowing Arsenal move saw Welbeck heel-flick the ball into the path of the unmarked Aubameyang, who beat Alex McCarthy to the ball to poke into the net.
The second was even more avoidable from a Southampton perspective, as when Welbeck received the ball on the left and roamed inside, the South Coast side ceased to close down the England forward. His eventually strike was tame and heading straight towards McCarthy who would have made a comfortable save, only for the ball to ricochet off Maya Yoshida and loop to the left of the stranded goalkeeper and into his net.
An acrobatic, albeit tame, effort from Chambers was this time easily held by McCarthy but Arsenal were beginning to assert their dominance on the game as it headed towards half-time.
McCarthy was forced into two excellent saves early in the second half by long-distance efforts from Granit Xhaka and Alex Iwobi - both well struck, powerful and heading towards the bottom left corner before McCarthy sprawled to keep the score down.
Those saves proved pivotal and Southampton entered their best spell in the game since the opening 20 minutes. Wesley Hoedt had headed a Ward-Prowse corner towards goal, only to watch on as Mohamed Elneny headed away from under the crossbar. Long was then denied a brace as he turned home Cedric's effort, but had his celebrations prematurely ceased by the assistant referee's flag.
Austin's introduction, replacing Yoshida, prompted a change in formation from a back 3-5-2 to a 4-4-2, and the switch had an immediate affect as the substitute netted the equaliser within a few minutes of entering the field of play. Cedric did excellently to make his way to the byline, before cutting the ball back for the former Queens Park Rangers man to continue his record of scoring in every appearance he has made against the Gunners.
But it was not to be a valuable point for Southampton, as Welbeck made up for missing a gaping, wide-open goal by climbing above the Southampton defence to nod home Iwobi's cross.
Jack Stephens and Elneny were both sent off as a well-tempered game became ill-disciplined in added-time. the Southampton defender retaliated to having his shirt pulled by Jack Wilshere by swinging an arm towards the England international, before Elneny shoved a Saints player as they prepared to take the resulting free-kick.
Mark Hughes' side remain 18th on 28 points, three below Palace, while the Gunners remain sixth on 54 points.