Arsenal punished struggling Southampton with two first-half goals to move back into the top four of the Premier League.
The Gunners led when Alexandre Lacazette reacted quickest to turn in Henrikh Mkhitaryan’s shot, with the Saints’ claims for offside proving futile.
And they doubled their lead shortly after when Mkhitaryan drilled a shot into the bottom corner.
Arsenal should have scored more in a dominant first half, but ultimately it mattered little as those goals were enough to move Unai Emery’s side above Manchester United, who drew at home to Liverpool.
Saints, who missed good chances through Nathan Redmond and Matt Targett before each of Arsenal’s goals, offered more resistance after the break.
But they remain in the bottom three, a point adrift of fourth-bottom Cardiff, after failing to win for a fourth successive league game.