Mikel Arteta dropped Pierre-Emerick Aubameyang from his squad because of a "disciplinary breach", but Alexandre Lacazette stepped up to open the scoring before Martin Odegaard added a second in the first half.

Gabriel netted a third after the break before Gabriel Martinelli and Bukayo Saka were each denied by the woodwork, with Southampton long since having given up on ending a winless run away at Arsenal that extends to 27 league matches.

The Saints are five without a win and just six points above the relegation zone, but victory moved Arsenal within a point of fourth-placed West Ham United.

Although Aaron Ramsdale denied Adam Armstrong and James Ward-Prowse as Arsenal started tentatively, the Gunners were soon ahead after a lovely passage of play was capped off by Lacazette finding the top-right corner following Saka's cutback.

It was 2-0 just six minutes later as Odegaard reacted fastest to Kieran Tierney's looping header and sneaked in to nod past Willy Caballero, the Norway international's third goal in as many games.

Odegaard looked to double his account after the interval but whipped over, while Nathan Tella forced another smart stop from Ramsdale.

Gabriel, who was earlier denied a goal for offside, then towered above Caballero to head home from Martinelli's corner, before the 20-year-old and Saka were thwarted by either post.

Nathan Redmond and Tella responded by inducing a further two saves from Ramsdale, but it was too little too late as the hosts cruised to a comfortable victory.

Arsenal hosts fellow European challenger West Ham on Thursday (AEDT), while Southampton travels to Crystal Palace on the same day.