Hector Bellerin struck an injury time leveller to secure a deserved point for Arsenal against Chelsea.
Marcos Alonso looked like he had won it for the Blues after a fantastic London derby before Bellerin's intervention.
Jack Wilshere opened the scoring for the Gunners, shortly after he should have seen red for diving, firing a fine strike past the otherwise excellent Thibaut Courtois.
But just moments later, Chelsea were level after Arsenal conceded another penalty.
Hector Bellerin caught Eden Hazard and the Belgian dusted himself down to score from the spot.
Alonso then turned home Davide Zappacosta 's cross to complete the turnaround.
Our man John Cross was at the Emirates and was impressed with Thibaut Courtois' performance.
Here are his complete player ratings.
Cech 7 - Made some super saves but feels like he will never reach his 200th clean sheet.
Chambers 6 - Horrible early mistake unnerved him but he did get better as game wore on.
Mustafi 7 - Played in middle of the three, looked the elder statesman, held it together.
Holding 7 - Booked. He has got so much promise, will still have nerve nights, but big future.
Bellerín 6 - Solid defensively but lacking that zip that used to see him fly down the right.
Xhaka 6 - Solid enough, some of his shooting was over ambitious and passing was patchy
Wilshere 7 - Booked. Fierce in the tackle, good passing and a brilliant goal. Terrific.
Maitland-Niles 7 - Power, pace and drive. He bossed Arsenal’s left side but undone on Chelsea’s second goal.
Ozil 7 - Arsenal’s driving force from midfield. Oozed class and quality but faded late on.
Sanchez 7 - Will still be wondering how he didn’t score. Good energy and work rate.
Lacazette 6 - Big miss in the second half. Arsenal’s £52m record signing still not convincing.
Welbeck (for Lacazette, 80)
Walcott (for Chambers, 82)
Subs not used
Mertesacker, Ospina, Iwobi, Coquelin, Elneny.
Courtois 8 MOTM - Made super saves - one from Sanchez and another from Lacazette the pick.
Azpilicueta 7 - So consistent and reliable. Kept Chelsea’s defence tight
Christensen 7 - Composed in the heart of Chelsea’s defence, reads the game so well and strong.
Cahill 7 - Solid performance for Chelsea, coped well with Lacazette’s runs and movement.
Moses 6 - Pushed back by Maitland-Niles and largely spent the night defending. Hooked early.
Fabregas 7 - Booked. Such a harsh booking - he got the ball. Could have scored, created chances.
Kante 7 - Solid all night, lovely distribution, back on top of his game again.
Bakayoko 5 - Should have scored, wasteful with his passing, still waiting for him to burst to life.
Alonso 6 - Good moments going forward, suspect in defence, rather typical display.
Hazard 7 - Always a threat, glides across the pitch. Won and converted the penalty. Class.
Morata 5 - Missed big chances for Chelsea. Could and should have had a hat trick.
Zappacosta 7 (for Moses, 56)
Drinkwater 6 (for Fabregas, 71)
Willian, for Hazard, 82
Subs not used
Caballero, Rudiger, Pedro, Batshuayi
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