Mauricio Pochettino made a winning return to Tottenham with Chelsea as his former club were reduced to nine men on a night of chaos and controversy.
The Argentine's comeback was reduced to a minor sub-plot by an epic game which brought five goals, a further five which were disallowed, two red cards, and a slew of VAR decisions in one of the Premier League's most frenetic ever encounters.
Spurs started brilliantly and deservedly went ahead when Dejan Kulusevski's sixth minute shot deflected in off Chelsea defender Levi Colwill, before Son Heung-min had an effort narrowly ruled out for offside as the home side looked to capitalise on their early dominance.
In a fevered atmosphere Chelsea had two goals of their own disallowed, one each from Raheem Sterling and Moises Caicedo ruled out for handball and offside respectively.
The latter situation still led to a Chelsea goal as a penalty was awarded for a crude challenge by Romero on compatriot Enzo Fernandez, and the Spurs defender was deservedly sent off in the aftermath.
Chelsea's summer signing Cole Palmer scored the resulting spot-kick to level the match before Spurs were also handicapped by what looked like a serious hamstring injury for key defender Micky van de Ven and an ankle problem for James Maddison as both players were substituted before the interval.
Spurs were battling an even greater disadvantage when Destiny Udogie was sent off ten minutes after the break for an inexplicably reckless tackle on Sterling which brought a second yellow card from referee Michael Oliver.
Ange Postecoglou, who also received a yellow card on the Spurs bench amid the mayhem, gambled on keeping a high line even with nine men but Chelsea finally broke their resistance with 15 minutes left, Raheem Sterling breaking clear to set up Nicolas Jackson for a simple finish.
The game was far from finished, though, and Spurs came close to securing a stunning draw as Eric Dier had a superb finish ruled out for a narrow offside and Rodrigo Bentancur headed just wide after beating Chelsea's defensive line at a late free-kick.
Jackson then scored twice more in stoppage time to secure a late hat-trick and render the scoreline far more comfortable than the evening had been for the visitors.
Lack of discipline costs Spurs on night which promised so much
Spurs fans were in buoyant mood before the game as they pondered the possibility of returning to the top of the Premier League, only to see their hopes extinguished in a spectacular, incident-packed game.
It all started so well with Kulusevski's goal but Spurs paid a heavy price for the reckless indiscipline of Romero, who was fortunate not to see red earlier than he did for kicking out at Colwill, but there was no escape when he followed through needlessly on Fernandez.
Udogie was also lucky not to be sent off before his eventual dismissal for a wild challenge on Sterling, and the Italy international left the over-worked Oliver with no option when he dived in on the same player early in the second half.
Postecoglou gambled on continuing with the high line and goalkeeper Guglielmo Vicario hero acting as an emergency sweeper on several occasions, but just as Chelsea started to look frustrated, Spurs were broken and Jackson cashed in with his hat-trick.
Aside from the short-term pain of this defeat, Spurs now face long-term consequences from the chaos, not just with suspensions for Romero and Udogie but those injuries to Van de Ven and Maddison.
Spurs supporters gave their players a rousing reception for their efforts at the final whistle but this was a painful night which could be very costly in the long run.
Chelsea and Jackson take big opportunity
Chelsea took their time to break down nine-man Spurs but eventually unlocked the defence, with Senegalese striker Nicolas Jackson the beneficiary.
Pochettino's men were already edging their way into the game even before Romero demonstrated his irresponsibility, but once he and Udogie were off Chelsea knew anything other than victory would have been unthinkable.
The home side made it to within 15 minutes of pulling off a remarkable draw before Sterling and Jackson finally cracked the code and this could be a landmark night for the 22-year-old striker, who has looked very much a work in progress since his summer move to Stamford Bridge.
He finish off three chances comfortably and marched off with the match ball, beaming in front of Chelsea's elated fans.
Pochettino will know this was not a victory earned in normal circumstances, but he will also aim to use it as a springboard after a middling start to the campaign.