Arsenal recovered from seeing David Luiz sent off to twice come from behind with 10 men and earn a 2-2 draw at Stamford Bridge on Tuesday.
Luiz was given his marching orders on 26 minutes for bringing down Tammy Abraham in the box as the England international was bearing down on goal.
A mistake by Shkodran Mustafi had allowed Abraham to go one-on-one with Bernd Leno and, after rounding the Arsenal goalkeeper, the forward was brought down by Luiz. Jorginho slotted home the resulting penalty.
Against 10 men, Chelsea dominated the opening stages of the second half, but were caught on the break from an attacking corner and Gabriel Martinelli profited from an N’Golo Kante slip to race through and equalise on 63 minutes.
Chelsea captain Cesar Azpilicueta thought he had earned all three points for the home side on 84 minutes as he finished off from close range, only for opposing skipper Hector Bellerin to curled home a second equaliser three minutes later.