The draw was far from ideal for either club, with the Gunners seven points off the top four, while the Saints remain rooted in the relegation zone and both teams looked as though they had lost at full-time.
Ralph Hasenhuttl’s men will leave the Emirates Stadium wondering how they didn’t snap their seven-game winless run, twice taking the lead through Danny Ings and James Ward-Prowse before missing several gilt-edged opportunities late on as Arsenal pushed for an equaliser.
Southampton were quick out of the blocks and deservedly took the lead after nine minutes when Arsenal were caught napping. Ryan Bertrand took a quick free-kick, resulting in Ings beating Bernd Leno at the near post for his seventh goal in his last 11 games.
Hasenhuttl’s team looked to take full advantage of an out-of-sorts home side, Ings shooting over from the edge of the box, while Stuart Armstrong fired across the face of Leno.
The equaliser came completely against the run of play, Kieran Tierney’s cross dropping to Pierre-Emerick Aubameyang, whose shot was blocked and fell to Lacazette to turn and fire home.
Arsenal changed to a back four in the second half, bringing on Nicolas Pepe and the club-record signing went close to putting the home side ahead when hitting the cross bar.
Aubameyang was also denied smartly by goalkeeper Alex McCarthy, while Nathan Redmond went close at the other end.
Hasenhuttl’s men were then gifted a chance to go ahead when Tierney pulled down Ings inside the box on 71 minutes. Ward-Prowse saw his initial penalty saved by Leno but tapped in the rebound to put the visitors back ahead.
Arsenal boss Unai Emery threw caution to the win in search of an equaliser, leaving his team exposed at the back, only for the Saints to fail to take advantage.
Substitute Moussa Djenepo missed two gilt-edged opportunities in the final 10 minutes, Joe Willock blocking one shot on the line, while Redmond and Sofiane Boufal also went close as Arsenal rode their luck.
Lacazette then popped in the 96th minute to rescue a point for Arsenal, poking home at the far post from Gabriel Martinelli’s cross.