Arsenal cruised to victory over a disjointed Southampton thanks to two first-half goals from Alexandre Lacazette and Henrikh Mkhitaryan at the Emirates, taking them back into the top four in the Premier League.
Arsenal took the lead in the sixth minute in bizarre circumstances, Lacazette neatly back-heeling in a pass from Mkhitaryan while the rest of the team were still appealing for a penalty after Lucas Torreira took a tumble in the box.
The home side doubled their advantage minutes later when Southampton keeper Angus Gunn, making only his second Premier League appearance, cleared the ball straight into the path of Arsenal's Alex Iwobi.
The midfielder bolted forward and passed across the goal to the unmarked Mkhitaryan, who thumped his shot low into the corner.
Lacazette should arguably have had a hat trick within the first half, but he was unable to take advantage of any of the numerous opportunities that came his way.
Southampton, by contrast, looked a shadow of the team that won the reverse fixture at St. Mary's in December, registering only three shots in the half to the hosts' 11.
They brought on Charlie Austin in the second half to see if he could maintain his record of scoring against Arsenal every time he has met them in the league, but the visitors were unable to break back into the game.
The result moves Unai Emery's side up into fourth place in the standings on 53 points after Manchester United were held to a goalless draw by Liverpool at Old Trafford.