Mauricio Pochettino will be absolutely fuming. Chelsea, in what was undoubtedly their best performance of the season so far, were flying against Arsenal, winning the individual battles all over the pitch. Step forward Robert Sanchez.
Eyebrows were raised when the Blues first bought the Spanish goalkeeper from Brighton to potentially be their number one, and his complete lapse in concentration here has cost his side big time. His lazy pass was picked off by Declan Rice and gave the Gunners a way back into a game they hadn't been in for 77 minutes.
Indeed, Cole Palmer - who looks a hell of signing - got the hosts off to the perfect start before a fortuitous Mykhailo Mudryk cross-shot put Chelsea in dreamland. It all started to fall apart after Sanchez's stupid error, however, with Leandro Trossard further spoiling the night with the late equaliser. Plenty of positives for the Blues, no doubt, but that'll be a sore one tonight.
GOAL rates Chelsea's players from Stamford Bridge...