John Terry's second-half header prevented Tottenham manager Andre Villas-Boas from claiming victory over Chelsea in a hot-tempered grudge match against former mentor Jose Mourinho.
The pre-match fireworks between the two managers had given an extra edge to what was already one of the most hotly-contested derbies in English football, and for the most part the game lived up to its billing.
Tottenham dominated the first half and took the lead through Gylfi Sigurdsson, but Terry - one of the personalities with whom Villas-Boas clashed at Chelsea - gatecrashed the Spurs boss' party to leave the score at 1-1.
Tempers often frayed during the match. Fernando Torres was sent off for two bookings - the last of which was a questionable one in which he was penalised for throwing an elbow at Jan Vertonghen when replays showed there was no contact.
The Spaniard could have been given a straight red for scratching the defender's face.
Villas-Boas and Mourinho had been practically inseparable for seven years, but the Spurs boss made it clear in the run up to the derby that he and his compatriot are no longer friends.
The two shared the weakest of handshakes before the game, and during the contest, it looked as though the master would be beaten by his old apprentice.
As Villas-Boas takes his ride around the M25 to Gatwick airport to catch his flight to Porto on Saturday night, he will be kicking himself about the result.
His Tottenham team had the upper hand over Chelsea for the majority of the first half and they could have had three or four by the break.
But Terry's goal, which came from a Juan Mata free-kick, means he will have to wait until March before he gets another chance to defeat Mourinho again.
Despite the booming noise of the pumped-up crowd, the opening few minutes were a tight affair.
Christian Eriksen almost created an opening with a free-kick, but Petr Cech had nothing to do until he was picking the ball out of the net.
Eriksen started the move, playing a flat ball across the box to Roberto Soldado who nudged the ball in to Sigurdsson's path.
Sigurdsson, so often Spurs' unsung hero, still had lots to do. He was off balance after taking an extra stride to beat Terry's outstretched leg, but he somehow managed to roll the ball into the net to the goalkeeper's right.
Villas-Boas savoured the moment with a double-fist pump while his opposite number was sullen and motionless.
The home crowd took great pleasure in taunting Mourinho, singing: "You're not special anymore."
Mourinho's team certainly did not look anything special. Tottenham were in complete control and it seemed certain they would double their lead before the break.
The brilliant Andros Townsend found Soldado on the right. The Spaniard spied Paulinho at the back post, but luckily for Chelsea, Branislav Ivanovic came to the rescue.
Chelsea started to improve slightly and Tottenham's nerves started jangling.
Eden Hazard robbed Kyle Walker on the edge of his own box, but Vertonghen got in the way to deflect his compatriot's shot wide.
Tempers frayed momentarily when Tottenham assistant Steffen Freund confronted fourth official Roger East after becoming annoyed about Mike Dean's officiating.
Townsend blotted his copy book by receiving a booking for diving while Eriksen entered the book for a petulant pull of Oscar's shirt.
Paulinho almost gave Spurs a second when he hit the woodwork just before half-time. That was Mourinho's cue to leave. He walked down the tunnel a minute before the half-time whistle. He had seen enough.
Whatever Mourinho said to his team at half-time, it had an effect.
The Blues, now with Mata on the pitch, started the second half well.
Torres cracked a low ball across the box, but it was just a touch too heavy for Oscar.
Lloris pulled off a top save to deny Torres, but moments later the Spaniard let himself down by appearing to scratch Vertonghen's face.
Torres, annoyed at what he thought was a dive from the Belgian, grabbed hold of the defender's face and dug his nails in to his skin.
Dean opted to book the striker.
The temperature reached boiling point again soon after when Ivanovic was booked for dissent. Vertonghen had another spat with Torres and the Belgian lost his cool moments later with a dangerous tackle on Ramires that caused Mourinho to spring from the bench and remonstrate with Dean from the touchline.
Spurs then paid dearly for Vertonghen's lapse in concentration from the resulting free-kick.
Mata put a high swirling ball in to the box, Vertonghen lost Terry for a second and he headed beyond Lloris before sprinting over to the ecstatic visiting fans.
Mourinho joined in the celebrations from the bench, but they were slightly restrained.
Torres then received a second booking. The Spaniard jumped with Vertonghen and the centre-back went down clutching his face. There was no contact between Torres' arm and Vertonghen's face, but Dean sent the Spaniard off.
The sending-off gave Spurs more momentum. Jermain Defoe and Sigurdsson almost snatched victory.
Villas-Boas and Mourinho shared a handshake at the end while Terry celebrated in front of his own fans.