Hector Bellerin grabbed a last-gasp equaliser for 10-man Arsenal in a 2-2 draw against Chelsea at Stamford Bridge on Tuesday as the visitors recovered from a first-half David Luiz red card to peg back the Blues twice in a pulsating London derby.
Top-four chasing Chelsea, seeking to put a stop-start run of performances behind them, started on the front foot and went ahead with a penalty by Jorginho in the 28th minute after Tammy Abraham pounced on a misplaced back pass by Arsenal defender Shkodran Mustafi and was brought down by Luiz.
The Brazilian - whose only other red card in the Premier League came when he was playing for Chelsea against Arsenal at Stamford Bridge in 2017 - was dismissed by referee Stuart Attwell before Jorginho stroked home from the spot.
Chelsea controlled the first hour of the match with winger Callum Hudson-Odoi hitting the bar and forcing Arsenal goalkeeper Bernd Leno into two fine saves.
But they once again failed to turn their possession into more goals and they paid for it in the 63rd minute when Gabriel Martinelli set off on a run from deep in his own half. He skipped past N'Golo Kante as the French midfielder slipped and fired past advancing Chelsea goalkeeper Kepa Arrizabalaga.
Chelsea, who lost 1-0 on Saturday away to Newcastle United despite also dominating that match, looked stunned at their latest setback before captain Cesar Azpilicueta stabbed home a cross by Hudson-Odoi in the 84th minute.
Arsenal refused to give up and their captain Hector Bellerin wrong-footed two defenders to create the space to score three minutes later with a curling low shot.
The result left Chelsea in fourth place, six points ahead of Manchester United and Wolverhampton Wanderers who have both played a game less. Arsenal remain in 10th place, 10 points behind Chelsea.
Chelsea coach Frank Lampard said his side were still struggling to turn their creativity into goals and had failed to follow their defensive instructions.
"We're in fourth position which is pretty good, but I know and we know there should be another 10 points on the board at least," Lampard told reporters. "All of us need to look at those final details."
New Arsenal manager Mikel Arteta said he told his players at the break that they could weather the storm after Luiz's dismissal.
"I sensed at halftime that they believed they could get back in the game," he said. "I wasn't expecting Hector to score with his left foot."