Kai Havertz and Gabriel Martinelli struck in 10 second-half minutes as Arsenal came from a goal down to secure a 3-1 win against Southampton.
In the week that Bukayo Saka said he expected this season to be the one that Arsenal would beat Manchester City to the Premier League title, Mikel Arteta's men were staring down the barrel of a shock defeat after Cameron Archer fired Southampton into the lead.
But Havertz hauled the Gunners level just three minutes later, with substitute Martinelli adding a second for the hosts after 68 minutes.
Southampton almost hit back - striking David Raya's woodwork twice in one minute - but Saka made sure of the points with two minutes remaining on another pivotal afternoon in north London. The Gunners remain level on points with rivals' City, and one shy of leaders' Liverpool.
Four days after their statement victory against Paris St Germain, Arsenal were back at the Emirates to face a side which had taken just one point from their opening six matches.
Aaron Ramsdale, who appeared 78 times in the Premier League for the Gunners, made his Emirates return - and the Saints stopper breathed a sigh of relief after just seven minutes when his sloppy clearance was pounced on by his former employers.
The ball fell to Declan Rice, who played in Gabriel Jesus. On his first Premier League start in an Arsenal shirt, Raheem Sterling was in the box and looking to pull the trigger but he was unable to get a shot away.
Arsenal were enjoying plenty of possession, but it was the visitors who registered the first shot on target.
Saka's clearing header fell only to Kyle Walker-Peters. The defender's shot, however, was straight down Raya's throat.
Arsenal had to wait until first-half injury time to record their opening attempt on Southampton's goal. Ramsdale parried Thomas Partey's strike, and Jan Bednarek was on hand to stop Sterling. Seventy per cent possession, 14 shots, and eight corners, but crucially no goals when the half-time whistle sounded.
And Arsenal might have fallen behind immediately after the restart. The impressive Tyler Dibling ghosted past Riccardo Calafiori before seeing his effort blocked by Gabriel, with Mateus Fernandes's follow-up just looping over Raya's bar.
Moments later, the Saints had their goal. Sterling was out-muscled by Fernandes in the centre of the park. The Portuguese played in Archer, who broke free of William Saliba in the area, and his strike nicked off the defender's toe, and into Raya's far corner with 55 minutes gone.
An upset suddenly looked plausible, but Southampton's lead lasted just three minutes.
Saka dispossessed Flynn Downes before finding Havertz in space, and a diving Ramsdale could do nothing to stop the German's pinpoint shot - his fourth goal in as many matches.
After a drab opening half, the game had come alive, and on the hour mark, Arteta introduced Martinelli and Leandro Trossard to save the day. And it was the former who did just that. Saka's fine cross found Martinelli unmarked, and the winger's side-footed volley went through Ramsdale's legs. A nervy VAR check for offside followed, but Arsenal survived.
Arsenal might have expected that to the end of it, but Dibley's deflected shot hit the foot of Raya's post with a dozen minutes to go. Raya then flapped at the corner, with the ball striking Adam Armstrong on the shoulder and hitting the crossbar.
But as the Saints pushed for an equaliser, Trossard broke free. Yukinari Sugawara's interception only fell to Saka, who blasted past Ramsdale to make sure of the win and maintain Arsenal's title tilt.
