Alexis Sanchez got the ball rolling as he marked his 100th Arsenal appearance with the opening goal, stealing in to rob Gary Cahill of possession before finishing well as Theo Walcott and Mesut Ozil also struck in a fine first-half for the hosts.

Arsenal may face Basle here in a Champions League game on Wednesday but, on the week of his landmark anniversary, this was the game Wenger would have been desperate to win.

He reaches his milestone on October 1 and, despite being in charge for two decades, the Frenchman had not tasted a Premier League victory over Chelsea in nearly a quarter of that time.

October 2011 was the last time he celebrated three points from this particular London derby and Arsenal had not even scored in the league against their rivals since January 2013 - but Wenger and his side were soon on their way to addressing that issue.

The hosts had flown out of the traps and were ahead as Cahill dallied in possession, with Sanchez nicking the ball of his toe, racing clear and lofting a smart finish over Courtois.

And their pacey start to the game continued as they doubled their advantage within three minutes, Walcott tapping home Hector Bellerin's cross after a slide-rule pass from Alex Iwobi.

Branislav Ivanovic nearly added to the defensive woes for Chelsea as his attempted clearance was blocked into the feet of Sanchez, who could only shoot tamely wide having opted not to pick out Walcott.

Chelsea looked threatening when they could muster an attack and Willian arrowed a shot across Petr Cech and wide after tenacious work from Eden Hazard.

But it was the hosts who would strike again before the interval as Ozil broke forward and found Sanchez, who lofted a ball to the back-post where the Germany international arrived to hit a volley into the ground and over Courtois.

Hazard flashed a shot into the side-netting as former Chelsea stopper Cech punched a free-kick into the Belgian's path, but the first half belonged to Arsenal.

The Gunners started where they left off after the interval as substitute Granit Xhaka freed Walcott down the right and the England international's cross was only inches too high for Sanchez to nod home.

Antonio Conte reacted by changing the shape of his side, introducing Marcos Alonso in place of former Arsenal man Cesc Fabregas and shifting to play 3-4-3.

But, after losing 2-1 to Liverpool last weekend, the Italian has now suffered back-to-back league defeats for the first time since 2009 and has plenty to address at Stamford Bridge.

Wenger's men have now won their last four in the league and are unbeaten in all competitions since the opening weekend of the season as he looks to usher in his 21st year in style.