Arsenal stung Chelsea with a stunning late fightback as they came from two goals down to snatch a 2-2 draw at Stamford Bridge.
Mikel Arteta's side looked to be heading to a first defeat of the season when Mykhailo Mudryk's cross-shot looped over David Raya minutes after the interval, adding to the lead given to them by Cole Palmer's first-half penalty.
The visitors were far from their free-flowing best and Mauricio Pochettino's side, inspired by the increasingly influential Palmer on the right of a front three, were for three-quarters of the game good value for what would have been a third straight league win.
But the pendulum swung when Robert Sanchez's careless pass presented the ball to Declan Rice who cut the arrears, before Leandro Trossard stunned the home fans into silence with a close-range finish in the closing minutes to earn Arsenal a draw and move them level on points at the top of the Premier League.
For the first time under Pochettino, Chelsea started without a recognised striker, Raheem Sterling instead lining up centrally, flanked by in-form pair Palmer and Mudryk.
They took the lead after 14 minutes. Sterling crossed from the right into the six-yard box, and as William Saliba leapt with an arm raised, Mudryk's header cannoned off it from close range. It took several minutes for referee Chris Kavanagh to be called to the pitchside monitor, but once checked there was little delay in awarding a penalty.
Palmer dispatched coolly past David Raya for his second Chelsea goal.
Arsenal had started sluggishly and it took until the 20-minute mark for their first opening, Martin Odegaard threading the ball into the left channel for Rice to stride onto, but his awkward right-footed effort clipped towards Sanchez's far corner zipped wide of the post.
Palmer has been one of the catalysts of Chelsea's sudden ascent to attacking potency under Pochettino, pulling strings whether collecting the ball deep or taking up a more advanced role. His impact was critical in consecutive wins against Brighton, Fulham and Burnley during which the team scored seven goals off the back of three scoreless matches, and here again he was the difference.
He had the chance to double the lead when Conor Gallagher, captain again with Reece James fit only for a late cameo, took the initiative and drove through the heart of Arsenal's midfield, slipping the ball in to Palmer who found room in between Saliba and Gabriel to get off a low drive which flashed inches wide of Raya's far post.
Chelsea might have pulled further clear in the closing minutes of the half, Sterling with a familiar burst down the right, slipping the ball to Malo Gusto who showed the finishing instincts of a full-back and ballooned over.
The second half began with a moment to forget for Arsenal goalkeeper Raya. Ben White gave the ball away to Gallagher inside the Chelsea half, and carrying the ball up the left flank he fed the overlapping Mudryk.
There seemed to be little on as the Ukrainian assessed options inside the box. Raya was positioned ready for a cross, but in doing so he left too much room behind him into which Mudryk's ball drifted, sailing clean over the keeper, who flapped helplessly as it landed in the net.
Raya's afternoon was going from bad to worse. Minutes after conceding, he was almost culpable for Chelsea's third when he rolled the ball recklessly to the feet of Palmer who narrowly failed to nip around the goalkeeper and bury Arsenal.
Then, with Arteta's side looking beaten, fortune turned in their favour. Rice hauled them back into it with 14 minutes to play and it was another goalkeeping error, this time from Sanchez.
Chelsea's summer signing has repeatedly been culpable in recent games of conceding possession with poor distribution. Here, under little pressure, he passed the ball straight to the feet of Rice, who with quickness of thought thumped it first time from 30 yards beyond the stranded keeper.
Then the final sting for Pochettino.
Bukayo Saka was given time on the edge of the box to shift the ball from right foot to left, and with vision and precision, he picked out the run of Trossard who stole in behind Chelsea with a lunging right leg to divert it past Sanchez.
