Eden Hazard reminded his new boss Maurizio Sarri of his quality with a game-changing cameo from the bench as Chelsea made it two wins from two and heaped further misery on Unai Emery and Arsenal with a manic 3-2 victory.
helsea went ahead through Pedro nine minutes in, before Pierre-Emerick Aubameyang missed an open goal. Alvaro Morata punished him by making it 2-0 at the other end immediately after, with Henrikh Mkhitaryan then replicating Aubameyang's horror miss.
But a crisp finish from Mkhitaryan made it 2-1 and then Alex Iwobi levelled it up before half-time.
Marcos Alonso slotted home from Hazard's assist in the 81st minute to edge Chelsea back ahead and it was enough to claim a 3-2 victory in the London derby.
It meant that new Arsenal boss Emery has suffered defeat in his first two games at the Gunners.
Chelsea defender Alonso said after a thrilling contest that his side merited the victory. "I think in the first half it was half and half, we started dominating and then lost a bit of space," he said.
"They played better at the end but in the second half we were the better team. It is three deserved points."
Hazard was full of praise for Sarri, with whom he shares his view on how football should be played. "He is the kind of manager who wants the ball, to control the ball. I can't say a wrong thing about that," Hazard said. "He is a great manager, like we had before."
Emery thought they "suffered" defensively after shipping three goals but was happy with the chances they created away from home.
He said: "We want to win. This is always the way but it is clear that defensively we suffered three goals but also we had chances to get more goals. In the first half we are creating chances to score, and for that I am happy. But also they had chances to score and that was the difference."