A star performance from Fraser Forster and a goal from Jan Bednarek condemned Arsenal to a third consecutive defeat, going down 1-0 at Southampton, which denied them the chance to close the gap on fourth place.
Forster made two impressive saves inside the opening 20 minutes to deny Gabriel Martinelli’s low shot and Bukayo Saka’s effort from close range.
Southampton were rewarded for their early resilience, taking the lead on the stroke of half-time when Mohamed Elyounoussi pulled the ball back for Bednarek to score at the near post.
Arsenal put the pressure on in the second half, but Forster continued to thwart them, brilliantly saving from Emile Smith Rowe, Saka and Granit Xhaka.
Southampton’s first win in five matches takes them up to 12th with 39 points.
Arsenal drop below Manchester United on goal difference to sixth on 54 points, three behind Tottenham Hotspur, who have played a match more.
Southampton: 21 Apr v Burnley (A)
Arsenal: 20 Apr v Chelsea (A)
Referee: Peter Bankes. Assistants: Neil Davies, Timothy Wood. Fourth official: Andre Marriner. VAR: Stuart Attwell. Assistant VAR: Sian Massey-Ellis.