Chelsea goalkeeper Mike Penders punched the ball into his own net before Mathys Tel struck a wonderful second to give Tottenham a rare but deserved 2-0 victory at Stamford Bridge in which Cole Palmer was sent off.
Spurs had won only one of their previous 34 Premier League visits to Chelsea, but delivered their best performance yet under Roberto De Zerbi, earning back-to-back wins within six days and easing concerns about a third season in the bottom half.
Xabi Alonso's decision to play without a recognised striker in the absence of the injured Joao Pedro backfired, with 19-year-old winger Geovany Quenda handed a first start and Morgan Rogers playing through the middle instead of the experienced Danny Welbeck.
Tottenham had 70 per cent possession in the first half and should have led when Omar Marmoush wasted a big chance from close range. Spurs goalkeeper Antonin Kinsky made saves from Cole Palmer, Jordan Henderson and Morgan Rogers, but Alonso clearly needed to change his line-up at half-time.
Instead, he stuck with it, and Tottenham became more dominant despite losing James Maddison to injury early in the second half, eventually taking the lead when Penders punched Mateus Fernandes' corner into his own net under pressure from Spurs centre-back Jan Paul van Hecke.
Chelsea's evening quickly worsened when Palmer received a second yellow card for standing on Conor Gallagher in a tackle.
Palmer had "lost his head", according to Your Site' Gary Neville, after avoiding a red card earlier in the second half for an off-the-ball incident when, with Fernandes on his knees having stopped the Chelsea forward's driving run, he barged into the Spurs midfielder's head, but escaped with only a booking.
Tottenham could not lose from there with 10 minutes left, but Tel made sure with a brilliant solo goal. He drove from deep on the left, cut inside, and fired low into the bottom-left corner to cap a statement victory under De Zerbi.
Tottenham head coach Roberto De Zerbi speaking to Your Site:
"It was a big moment for the fans, the club and the players. They deserved this win and prepared very well. We are improving a lot in our mentality, as a group and in our relationships with the players. We are also improving on the pitch.
"Against Aston Villa and Everton, for 30 minutes we were playing very well. Maybe we didn't score because our finishing wasn't good enough, and perhaps in the first difficult moment we changed our mentality.
"Now we are a complete team. The players are playing better and we have improved our style."
Chelsea manager Xabi Alonso speaking to Your Site:
"Collectively and individually, I do not think we were at our best level. The game was about the first goal and in the second half it went their way and then with 10 men it was difficult."
On red card being a learning curve for Palmer: "Yeah absolutely. I haven't seen it on TV but I've been told [the referee] probably got it right.
"We hadn't received any red cards and we need to continue that way because we need to have this maturity to deal with difficult moments. When you have conceded there was still probably 15-20 minutes to go. I need to check the action to talk with Cole but it is one to learn from in the future for sure."
Your Site' Daniel Sturridge:
"The manager got it wrong in terms of playing Quenda. The way in which they have played in the last couple of weeks, if Joao Pedro doesn't start, then the formation changes. For Rogers and for Palmer, it has an impact on their natural way of playing, having a focal point.
"Is he as fast? No, but he could've come in and done a job. Welbeck should've started today, it would've let the team be what they have been.
"[Nicolas] Jackson is flying at the moment, should they have kept him?"
