Marcos Alonso scored the winning goal as Chelsea battled past Arsenal in an enthralling contest at Stamford Bridge.
Alonso found the net nine minutes from time after the influential Eden Hazard picked him out.
Chelsea had looked set for a dominant victory after early strikes from Pedro and Alvaro Morata, but Henrikh Mkhitaryan inspired a rally from the Gunners, scoring his side's first before assisting Alex Iwobi.
The second half was notably cagier than the wide-open first, but it was Maurizio Sarri's Chelsea who nicked the three points to go top of the Premier League on goal difference.
Arsenal torn apart before turning game on its head
It was Chelsea who started the game in control, stroking the ball around with confidence and precision as Arsenal struggled to put together any extended spell of possession.
Pedro produced the first effort of any real significance on four minutes when he raced inside and bent one wide of Petr Cech's right-hand post.
Moments later, Ross Barkley found an alarming amount of space on the edge of the area but could not bring down Jorginho's clipped ball.
Arsenal then threatened to snatch an opener against the run of the play, with Mesut Ozil diverting Nacho Monreal's cross just past the far post.
Just a minute later, though, Chelsea grabbed a deserved lead, with Pedro calmly applying the finishing touch after Alonso, set free down the left, squared it to him. The Arsenal defence was nowhere to be seen.
The Gunners subsequently found themselves hemmed in and struggling to repel Chelsea's advances.
N'Golo Kante snuck in behind the defence and pulled the ball back to Barkley, who fired it a matter of inches over the crossbar.
Arsenal were clearly rattled but did manage to carve out a couple of chances. First, Pierre-Emerick Aubameyang, picked out by Shkodran Mustafi after making a good crossfield run, evaded David Luiz but fired straight at Kepa Arrizabalaga.
Shortly afterwards, the Gabonese striker produced an early contender for miss of the season after Arsenal sliced through the Chelsea backline.
Matteo Guendouzi found Hector Bellerin with a defence-splitting ball, but Aubameyang somehow managed to blaze it over the top when the Spaniard picked him out.
Chelsea's second, which came within a minute, seemed a brutal blow in such circumstances.
Cesar Azpilicueta found Morata, between the Arsenal centre-halves, and he proceeded to race through, beat Mustafi and calmly roll it past Cech. It was a very well-taken, morale-boosting goal for the much-maligned frontman.
It seemed a question of how many at that stage but Arsenal's response was impressive this time.
They very nearly found a way back into the game on 32 minutes, but Mkhitaryan came up with a miss alarmingly similiar to that of Aubameyang when he saw his effort sail over the crossbar after it broke to him into the area.
It did not take long, however, for the winger to make amends. Five minutes after spurning the glorious chance, he was found by Iwobi's deflected pull-back and stroked the ball into the bottom left corner.
Arrizabalaga may have been disappointed after getting a touch as he tried to palm it away.
Chelsea's initial response was good, with Cech forced to tip Morata's long-range side-footer over the bar, but on 41 minutes Arsenal were, somewhat miraculously, level as Iwobi dispatched Mkhitaryan's driven cross.
Again, Arrizabalaga got a hand to the ball but there was little he could do on this occasion.
The visibly emboldened Gunners should really have completed the turnaround before the break.
Aubameyang saw a close-range effort trundle the past the post after failing to strike the ball cleanly before Iwobi skied a gilt-edged opportunity from another cut-back, lacking the required composure.
Hazard introduction decisive in tighter second
With both managers likely reeling from their side's defensive woes, the second period was significantly more congested.
Chelsea were on top, though, and had an appeal for a penalty waved away on 52 minutes when Kante's driven shot struck the hand of Sokratis.
Replays showed that the Greek defender had unintentionally handled the ball, but only as he fell to the floor after making the initial block.
The tireless Barkley went close just before the hour mark, fashioning some space, firing across goal and forcing Cech into a good save.
It would prove to be the former Everton's man last contribution as he was withdrawn on the hour in place of Hazard, who predictably injected fresh life into the match.
His threat was underlined when he beat Bellerin and zipped one across goal from the byline, with no Chelsea attacker able to prod it home.
Arsenal substitute Aaron Ramsey also looked to take the game by the scruff of the neck and tested Arrizabalaga with a low shot which the new arrival just about gathered.
Still Chelsea looked the more likely as Hazard and Alonso repeatedly found space down the left-hand side.
The full-back's whipped ball was met by Kante as the game entered its closing stages, but the diminutive Frenchman looped his header over.
On 81 minutes it was Hazard's turn to create some room by gliding past Alexandre Lacazette, and this time Alonso was on hand to slot the ball underneath Cech and into the net from the pull-back.
Ramsey's ambitious half-volley, which landed on the roof of the net, was the closest Arsenal would come to snatching a point from the jaws of defeat.
Had Cech not stood tall to twice deny Hazard and prevent Olivier Giroud scoring against his former club, the victory would have looked comfortable.
The season's second meeting of 'big six' outfits, then, was a near-classic, but both teams have significant defensive work to do before they return to action against West Ham and Newcastle respectively.