Dele Alli continued his scintillating form in front of goal by heading a brace to give Tottenham a stirring 2-0 derby victory and halt Chelsea's record-equalling Premier League winning run of 13 matches.
Alli scored twice for the third Spurs game in succession, converting Christian Eriksen crosses either side of half-time as Antonio Conte's league leaders tasted defeat for the first time since September.
Tottenham are up to third place, above Manchester City on goal difference, and now within seven points of Conte's men, who lead Liverpool by five.
Mauricio Pochettino's side are enjoying a purple patch of their own, having won five from five since losing at Manchester United on December 11 and scoring 15 times in the process.
Chelsea's rampant march had previously been tested as they fell behind to Spurs at Stamford Bridge and City at the Etihad Stadium, but the excellent Alli ensured there would be no respite on this occasion.
Tottenham began with menacing intensity but Eden Hazard enjoyed the first clear opening for the leaders in the fifth minute, only to scuff wide from Nemanja Matic's ball over the top.
Mousa Dembele strode through a succession of Chelsea challenges before his chipped pass ran a shade too far for Harry Kane, while Eriksen was afforded a couple of set-piece opportunities as Spurs increased the pressure.
Pedro – back in the Chelsea XI for Willian following suspension despite the latter's brace against Stoke City – was booked for bringing down Danny Rose and found himself embroiled in a heated exchange of views with Diego Costa after a counter-attack broke down.
Eriksen flashed a dipping drive just past the post in the 23rd minute and Costa blazed over from the edge of the box 10 minutes before half-time.
Chelsea goalkeeper Thibaut Courtois parried Eric Dier's back-post header after Gary Cahill was cautioned for hauling back Eriksen and the Denmark international rounded off a highly impressive first period by setting up the opener in stoppage time.
He was given room to float an impeccable cross towards Alli, who timed his run to leap and guide a header into the top right corner.
Spurs goalkeeper Hugo Lloris was seldom involved before the break but got down with a firm hand to keep out Costa two minutes after the restart, while Hazard squirted a header wide after the hosts failed to deal with Marcos Alonso's deep cross.
Once more, Alli emphatically showed him how it was done in the 54th minute.
Eriksen again took on the role of provider and the England star found space in between Victor Moses and Cesar Azpilicueta to beat Courtois at the far post.
Alli's clever movement and relentless running meant the evening never progressed beyond unpleasant for Chelsea's much-vaunted defence, although he was unable to extend his hot streak to eight goals in four games by claiming the matchball.
Tottenham comfortably closed out a victory to serve emphatic notice of their own title ambitions against the opponents who so relished ending them last time around.
