Maurizio Sarri's Chelsea maintained their 100 per cent record meaning Unai Emery's Arsenal has yet to open their account. Chelsea were deserved winners on a day where the inconsistent Arsenal could have easily stolen all three points if they had taken their chances in front of the goal.
Chelsea made a thumping start, with Jorginho the orchestrator for the attack and Alonso the provider for the opening goal for an easy side-foot finish for Pedro, where Arsenal's defence went to sleep.
After opening the scoring, Chelsea doubled their lead with a neat finish by Morata, who took a long ball from Azpilicueta that completely caught Arsenal's defence except for Mustafi, who failed to clear the danger.
Arsenal fought back brilliantly with some after missing easy chances with quick goals from Mkhitaryan and Iwobi, with both goals that were well crafted by Arsenal full-backs that looked pleasing to the eyes as they finished the first half on high.
Although Arsenal showed great spirit to come back from 2-0 down to level the score 2-2, it was Chelsea who had the last laugh with Marcos Alonso scoring the winner after a special cameo by Eden Hazard, whose added quality provided the spark to seal the match.
Chelsea Player ratings
Kepa Arrizabalaga 6
He should have dealt with Mkhitaryan's goal besides that had a decent game.
Cesar Azpilicueta 7
Provider for Morata's goal, he surely has great coordination with his fellow Spaniard but he should have covered Arsenal's attack for their second goal.
Antonio Rudiger 6.5
He had a solid game, but occasionally left space for the opposition attackers.
David Luiz 5.5
The Brazillian was horrendous at back, he was the culprit for Arsenal's comeback an erratic display from him.
Marcos Alonso 8
Helped Pedro to open the scoring and scored a late winner to seal the game. He surely is one of the best left-backs right now.
Jorginho 8
Showed his class today as he demonstrated with his wide range of passing and creativity why he is a top midfielder in the league. He was involved in the opening goal with a pass to Alonso on the left.
N'Golo Kante 7.5
He played a more attacking role than he usually does, he was brilliant going forward and should have scored in the second half as he placed his header over the bar.
Ross Barkley 7
Had a good game with an all-round display in midfield as he looked like a good workhorse, he also had a couple of shots on goal that were saved.
Willian 6
Willian worked the ball well on the wings to create trouble inside the opposition's box but those failed to produce any output.
Alvaro Morata 7
Silenced many critics with his goal and probably much-needed confidence in him after an underwhelming season.
Pedro 7.5
Scored the opening goal with a neat finish, looked lively on the right side with his link-up play and caused all sorts of problems for Arsenal's full-backs.
Mateo Kovacic (for Barkley 59') 7.5
Industrious, made some fine interceptions, his mobility, awareness and passing was top class and he looked like a real deal.
Hazard (for Willian 61') 8
A player whose quality is immaculate, his substitution caused havoc in Arsenal's defence and eventually assisted Alonso after testing the goalkeeper himself. He was the difference in the game between the two sides.
Olivier Giroud (for Morata 74') 5
He was always an aerial threat as usual but couldn't have much impact on the game.