LONDON — Harry Kane scored twice as Tottenham overwhelmed Chelsea 5-3 in an electrifying London derby on Thursday to enhance its top-four credentials while ensuring its neighbor's English Premier League lead was wiped out.
The New Year's Day capitulation was only Chelsea's second loss of the season and the first time that a Jose Mourinho Chelsea side had conceded so many times in the league, including his 2004-07 reign.
Such was the frenzied nature of the game, the most significant result of Mauricio Pochettino's first season at Tottenham looked uncertain until the closing stages, with goals gifted by both teams. Even sweeter for Spurs was the win taking them above north London rival Arsenal into fifth place, only two points from the top four.
"With a victory like today you can improve quicker," Pochettino said. "We have improved a lot in the last months. We are stronger now."
Having started 2015 with a three-point lead, Chelsea became level with Manchester City after the champions beat Sunderland 3-2, separated in the standings only by alphabetical order.
Although Diego Costa put Chelsea in front, Kane leveled with his first goal on the half-hour, while Danny Rose and Andros Townsend's penalty gave Tottenham a halftime lead.
Either side of Nacer Chadli's fifth for Tottenham, Eden Hazard and John Terry scored for the visitors but they couldn't prevent Chelsea losing for the first time since 2010 to their north London rivals.
"We made some defensive mistakes," said Mourinho, whose side was held by Southampton on Sunday. "Plus we were unlucky in every rebound and deflected shot."
Chelsea had led in the 18th minute. Hazard darted past Rose and was denied by the post, but Oscar sent the ball back across the face of goal and Costa was primed to tap into the net.
But the impetus was soon with Tottenham again after another moment of individual quality from this breakthrough season for Kane. The 21-year-old forward waltzed in from the left facing little resistance before powering the ball past goalkeeper Thibaut Courtois.
With the turn of the year, Chelsea's usual solidity at the back appeared to have been left in 2014.
The visitors were behind after Christian Eriksen slid the ball through for Nacer Chadli to clip it past the onrushing Courtois. Although Chadli hit the post, the left back Rose ran into an advanced position and resisted Cahill's sliding challenge to bury the follow-up in the net.
Tottenham wasn't finished before the break.
Kane, so troublesome for the Chelsea defense to contain, was tripped by Cahill on a woeful day for the England center back. And Townsend netted the resulting penalty kick, prompting Mourinho to storm down the tunnel before the teams could leave for halftime.
When Mourinho re-emerged for the second half, he was having words with referee Phil Dowd. What Mourinho was complaining about was unclear.
What was clearer was Chelsea's inability to contain Kane, who cut inside in the 52nd and put the ball between Terry's legs to score his 16th goal of the season.
"We need to be careful with him," Pochettino said of Kane. "He is still young. It's impossible to hide him because of his performances."
Tottenham's defense was less impressive.
On the hour, Federico Fazio was dispossessed near the halfway line, Hazard seized the ball, and played a one-two with Cesc Fabregas before dispatching the ball low past goalkeeper Hugo Lloris.
Mourinho was getting increasingly irate on the touchline, berating fourth official Andre Marriner with an expletive. And Marriner faced further fury from Mourinho after a penalty was not awarded for Fazio's push on Hazard.
There could be no complaint about Tottenham's fifth. Kane worked the ball down the left flank and passed to Chadli, whose deflected shot beat Courtois in the 78th.
But Chelsea was gifted a third when Hazard's cross was turned on by Branislav Ivanovic for the unmarked Terry to score the goal that kept his team on top of the league. Chelsea and City have the same goal difference, and both have 44 goals in 20 games.