Chelsea came from 4-1 down to draw 4-4 from Ajax in an epic encounter which saw the Dutch side lose two players to red cards in one minute.
The Blues came into this clash in top spot following their 1-0 victory over Ajax on head-to-head with both sides on six points.
However, the visitors took the lead inside two minutes as Quincy Promes' whipped free kick found the back of the net via a deflection from Chelsea forward Tammy Abraham.
But Ajax weren't ahead for too long as Christian Pulisic was brought down in the penalty area and Jorginho tucked home the resulting spot kick to make it 1-1 after just four minutes.
Abraham then had a coolly taken goal ruled out for offside before Erik ten Hag's side re-took the lead on 20 minutes when Promes snuck in behind the Chelsea defence to head home from Hakim Ziyech's cross.
The Amsterdam giants then made it 3-1 on 35 minutes after Ziyech's free-kick from just in front of the corner spot on Chelsea's left hit the far post and rebounded off Blues goalkeeper Kepa Arrizabalaga and into the back of the net.
Chelsea came out with purpose at the start of the second half as they looked to get back into the match with defender Kurt Zouma producing a superb, mazy run before he blazed over.
And, against the run of play, Ajax made scored a fourth 10 minutes into the second half as Donny van de Beek finished off from another Ziyech lay-off and it appeared the game was over.
However, Cesar Azpilicueta tapped home for Chelsea on 63 minuts to reduce the deficit before the game then completely turned on its head on 68 minutes as Ajax lost Daley Blind to a red card after he picked up a second yellowfor a foul on Abraham.
Initially, referee Gianluca Rocchi played an advantage, before he pulled the game back after a Joel Veltman handball in the box. The Netherlands international also received his marching orders and Jorginho tapped home from the penalty to make it 4-3.
And the Chelsea pressure told as they drew level 4-4 on 74 minutes as Reece James finished off after Abraham had hit the bar.
Azpilicueta then had a fifth goal ruled out following a VAR decision before Ajax's Edson Alvarez came close putting Ajax back in front late on and Michy Batshuayi fired wide in stoppage time.