Ajax, semi-finalists last season, were in calm control and looked on course for victory when Donny van de Beek gave them a three-goal advantage 10 minutes after the break – but in a chaotic closing period Chelsea completed a remarkable recovery as the visitors lost their discipline.
Tammy Abraham’s own goal gave Ajax an early lead and even though Chelsea were quickly on terms through Jorginho’s penalty, they were in trouble at half-time after Quincy Promes headed in a brilliant cross from Hakim Ziyech, who then saw his free-kick inadvertently deflected in by keeper Kepa Arrizabalaga.
Van de Beek looked to have settled matters but Cesar Azpilicueta pulled one back for Chelsea, before Ajax lost Daley Blind and Joel Veltman within a minute to second yellow cards, with the dismissals followed by a penalty which Jorginho scored again to set up a frantic finale.
Reece James then pulled Chelsea level and Azpilicueta thought he had scored the winner, only for the video assistant referee to intervene and detect a handball by Abraham.
Both sides had chances in the closing moments but in the end settled for a draw which leaves them level on seven points, along with Valencia who beat Lille 4-1 in this extremely tight Group H.
Chelsea dig deep to earn reward
One look at the Group H table shows how important this point might be to Chelsea before a potentially decisive visit to Valencia next, on 27 November.
For the first 55 minutes, Chelsea looked naive and exposed at this level as they were cut apart by Ajax’s slick approach work and lethal delivery from out wide, which was instrumental in their first three goals.
When James levelled it up at 4-4 with 16 minutes left, all the smart money would have been on Chelsea completing the turnaround with victory.
It almost came as Azpilicueta saw his goal overruled by VAR, with the refreshing sight of referee Gianluca Rocchi actually consulting a screen to decide for himself, and with two late chances for substitute Michy Batshuayi, one of which brought a superb save from Ajax keeper Andre Onana.
In the end, Chelsea had to settle for a share of the honours – something they would have readily accepted after 55 minutes but which they might have taken with slight disappointment at the end.
This was a thrilling spectacle in which both teams deserved some reward.