Arsenal needed to come from behind to win a breathless game 2-1 against Chelsea at the Emirates Stadium as Kai Havertz scored for the third time in the Premier League against his former club.
Havertz netted midway through the first half to equalise after Morgan Rogers, who the champions missed out on signing during the transfer window, had stunned home fans with a volleyed goal after 77 seconds.
The Germany international was instrumental too in Martin Odegaard’s 50th-minute winner, executing a delightful dummy to leave Chelsea’s defence flatfooted and create room for the captain to rifle home.
Chelsea had lost four league games in a row at the Emirates, conceding 11 goals, but here they gave Arsenal a far sterner examination than at any time during that sequence, with the front three of Cole Palmer, Joao Pedro and Rogers again showing their potential as assets in a possible title challenge.
Yet Xabi Alonso appeared no closer to solving the enigma of a team so irresistible in attack yet too easily pulled into all the wrong shapes defensively and in midfield.
In truth, Arsenal’s play and Chelsea’s wobbles ought to have brought victory by a larger margin, Emiliano Martinez with a wonderful stop to deny Bukayo Saka, before David Raya gave a reminder of his own indispensability with an even better save to keep out Estevao.