A last minute penalty from Arsenal’s Santi Cazorla condemned unlucky Southampton to defeat at Emirates Stadium.
Ahead of the contest Saints were chasing a fourth game unbeaten against the Gunners and put themselves on course to keep that run going when Dušan Tadić’s 18th minute free-kick bounced in off the crossbar and goalkeeper Petr Čech to put the visitors in front.
That was the first time Claude Puel’s men had led in a game this season, but they were pegged back on the half hour from an unlikely source as defender Laurent Koscielny produced an acrobatic overhead kick which went past Fraser Forster.
With the score level at half-time, Saints introduced Shane Long in place of Jay Rodriguez up front, and the Irishman carved out a few more openings for the visitors, including a notable one-on-one with Čech which just went wide.
As time slipped by, Arsenal changed their options with Olivier Giroud and Alexis Sanchez entering the action, and the former would go on to play a big part in the deciding goal of the game when he was adjudged to have been fouled by Saints skipper José Fonte inside the area as stoppage time began.
After a melee inside the area, Cazrola dusted himself down to fire in the wining strike from 12 yards, to leave Saints on the end of an unlikely defeat on the balance of play.
Prior to the game, three changes were made to the team by Puel who brought in Ryan Bertrand, Jordy Clasie and Rodriguez to his starting line up.
All three were influential in an energetic first half display from Saints, who deservedly took the lead just past the quarter hour mark.
Redmond was hauled down outside of the area, and with Van Dijk and Tadić hovering over the set-piece, it was the latter’s effort which dropped down off the underside of the crossbar and crept over the line off the back of Čech.
Having looked the more dangerous side Saints seemed comfortable in the game, but Koscielny’s improvised effort before the break got the Gunners back into it.
It was a quiet showing from former Southampton pair Theo Walcott and Alex Oxlade-Chamberlain, but both were involved in sweeping moves forward from the hosts who were dangerous on the break.
Cazorla was Arsenal’s main man, and having spent much of his afternoon trying to tee up his teammates, it was down to the midfielder to take responsibility late on which he did unerringly to take the three points for Arsène Wenger’s side.
For Saints, they now host their first UEFA Europa League game of the season on Thursday against AC Sparta Praha searching for their first win of the season, but if they play like they did in north London, then they won’t be far away from doing that.
Arsenal: Petr Čech (GK), Laurent Koscielny (c), Nacho Monreal, Hector Bellerin, Shkordan Mustafi, Francis Coquelin, Mesut Özil, Alex Oxlade-Chamberlain (Alexis Sanchez 62), Theo Walcott (Alex Iwobi 75), Santi Cazorla, Lucas Perez (Olivier Giroud 62).
Unused substitutes: David Ospina (GK), Rob Holding, Granit Xhaka, Mohamed Elneny.
Booked: Monreal, Cazorla
Goals: Koscielny (30), Cazorla (pen 90)
Southampton: Fraser Fortser (GK), Cédric, José Fonte (c), Virgil van Dijk, Ryan Bertrand, Oriol Romeu, Steven Davis, Jordy Clasie (Pierre-Emile Højbjerg 63), Dušan Tadić (James Ward-Prowse 80), Nathan Redmond, Jay Rodriguez (Shane Long 46).
Unused substitutes: Alex McCarthy (GK), Maya Yoshida, Matt Targett, Charlie Austin.
Booked: Forster, Højbjerg, Fonte, Van Dijk, Bertrand
Goal: Tadić (18)
Referee: R. Madley