Chelsea battled back from three goals down to earn a 4-4 draw in Tuesday's thrilling Champions League clash with Ajax, who were made to pay for two red cards at Stamford Bridge as the hosts were denied a dramatic winner by VAR.
Frank Lampard's side conceded three first-half goals in the competition for the first time as Tammy Abraham and Kepa Arrizabalaga both put into their own net, either side of Jorginho and Quincy Promes netting.
Ajax opened up a 4-1 lead through Donny van de Beek early in the second half and were still 4-2 in front - Cesar Azpilicueta pulling one back - when Daley Blind and Joel Veltman were dismissed in the space of a minute.
Jorginho scored his second penalty of the match to reduce the arrears and substitute Reece James struck 16 minutes before Chelsea had a late Azpilicueta goal ruled out by VAR, leaving them second in Group H behind Ajax.
Ajax lost 1-0 to a late Michy Batshuayi strike when the sides met in Amsterdam two weeks ago but were ahead early on here, with Abraham swinging at Promes' cross and sending it past Kepa with a slight touch.
That was the second-earliest goal conceded by Chelsea in the competition but they levelled through Jorginho's penalty after Joel Veltman fouled Christian Pulisic in the box.
Abraham had a goal ruled out for offside and the visitors were back in front 20 minutes in when Promes reacted quickest to guide Hakim Ziyech's cross away from Kepa.
Ziyech was again involved for Ajax's third goal, the midfielder's whipped free-kick hitting the crossbar and bouncing off Kepa's face before crossing the line.
Van de Beek appeared to have killed off the game when picking up a loose ball and slotting past Kepa, but Azpilicueta prodded home from close range to restore hope.
Blind fouled Abraham in the box but play continued and Veltman handled Callum Hudson-Odoi's cross, leading to a penalty being awarded and both Ajax players being shown second yellow cards.
Jorginho calmly dispatched the spot-kick and just under three minutes later full-back James walloped home after Abraham's header crashed back off the crossbar.
Chelsea skipper Azpilicueta thought he had sealed an incredible comeback with a fine finish inside the box, only for VAR to spot a handball by Abraham in the build-up.
What does it mean? Ajax take top spot despite collapse
Chelsea ceded control of top spot despite their remarkable revival. Valencia's 4-1 win over Lille in the other Group H contest today means three sides are locked on seven points apiece with two matches still to go, with Ajax at the summit.
Ziyech gives Chelsea the blues
Eight goals were scored at Stamford Bridge in a Champions League classic and Ziyech played a direct part in three of them.
As well as setting up Promes and Van de Beek, he also caught out Kepa - the player credited with Ajax's third goal - with an audacious attempt from a wide free-kick. Only Ziyech will know whether it was intended as a shot or a cross.
Chelsea's defence bailed out
Chelsea's entire back four were once again incredibly sloppy and, unlike in Amsterdam two weeks ago, Ajax made them pay time and time again.
Marcos Alonso returned to the starting line-up and was particularly culpable, but he was bailed out by three goals in 11 minutes from his team-mates.
Key Opta Facts
- Chelsea are the third English side in Champions League history to come from three goals behind to avoid defeat and the first since Liverpool in May 2005 (3-3 v AC Milan).
- Chelsea have conceded four-plus goals in a single Champions League game for only the third time in their history and first time since drawing 4-4 at home to Liverpool in April 2009.
- Ajax have scored four-plus goals in a game against an English team in all European competition for only the second time (also 5-1 vs Liverpool in December 1966 at home in the European Cup).
- Reece James (19y, 332d) became Chelsea's youngest ever goalscorer in Champions League history.
- Ajax's Hakim Ziyech has either scored or assisted in nine of his last 12 Champions League appearances (4 goals, 6 assists).
Chelsea are back in Premier League action at home to Crystal Palace on Saturday, while Ajax host Utrecht in their next Eredivisie outing on Sunday.