Marcos Alonso scored late to condemn Arsenal to their second successive Premier League defeat.
Unai Emery is still yet to get off the mark following a thrilling game at Stamford Bridge.
The five-goal thriller provided constant entertainment – but also plenty of evidence that the best either of these teams can aim for in this season’s Premier League is a top-four finish.
Arsenal fell behind after just nine minutes when Pedro turned in Marcus Alonso’s low cross.
Alvaro Morata then added another seconds after Pierre-Emerick Aubameyang missed a sitter.
At 2-0, Arsenal appeared set for a long afternoon, but the Gunners fired back into the game through Henrikh Mkhitaryan whose low shot was enough to surpass Chelsea’s new £71m keeper Kepa Arrizabalaga. Alex Iwobi then put the Gunners on level terms.
After an even second-half, the Blues sealed the win late on when Alonso sweeped in Eden Hazard’s cross.
Thoughts on the defeat, Gooners? Let us know in the comments…