Tottenham Hotspur 5 Chelsea 3

This was the evening Chelsea's title pursuit, for the first time this season, was made to look fragile. Even unlikely. A side who had prided themselves on an ability to ally thrilling attacking play with stingy defence were picked apart and embarrassed, wilting in the face of Tottenham Hotspur's eager energy, bright attacking threat and a homegrown forward who has never played better. Harry Kane will cherish memories of this occasion.

The England under-21 international scored twice, earned a penalty and supplied Nacer Chadli with the hosts' fifth as the majority at White Hart Lane revelled in a victory that felt barely credible.

José Mourinho's teams are not thrashed in this way. Never before had he conceded four while in charge of Chelsea, and this was only the second time in his managerial career he had watched helpless as his charges shipped five. The new year has already seen their lead at the top shredded. Manchester City boast an identical record at present courtesy of a winning goal plundered by Frank Lampard up at the Etihad stadium earlier in the day. The title race is digesting a new twist.

Perhaps the onerous schedule, with this a third awkward away trip in four matches over the festive season, had dulled Chelsea's approach. Certainly their opening here was sluggish, the defence uncharacteristically jaded and the upbeat rhythm that has been a trademark of the campaign to date only summoned in the period immediately after they took the lead when Eden Hazard, Oscar and Willian tore into Spurs and Diego Costa was such a menacing presence at the tip of the team.

The Spain international had poked them ahead on the break after steady Tottenham pressure. For a while in the one-sided period that ensued it appeared another routine victory had beckoned in a season of regular comfortable successes. And yet by the break, with Mourinho turning on his heel and heading down the tunnel in disgust, their evening had been transformed for the worse.

The visitors' goal had been pilfered on the counter. Tottenham had lost Ryan Mason to a hamstring injury and were still infuriated at Thibaut Courtois's fine one-handed save to deny Chadli's overhead kick when the goalkeeper collected a corner and flung the ball 60 yards to Hazard on the right touchline. The Belgian retained his balance as Danny Rose pushed him in the back, and survived an appeal that the ball had drifted out of play, to leave the full back gasping in his vapour trail and drill a shot against the far post. Costa had dangled a leg at that effort from an offside position but Oscar collected at the far post and, when he fired back across the diving Hugo Lloris, the forward poked in from close range. Kyle Walker's presence on the post ensured no assistant's flag would save the hosts.

The concession deflated Spurs, their initial urgency long since fizzled out, but, critically, Chelsea could not glean further reward. There were appeals for handball against a grounded Jan Vertonghen at Oscar's touch, but the visitors felt comfortable and commanding.

Then, from a position of authority, their defence disintegrated. In the 15 frantic minutes up to the interval they imploded, an inability to close down Kane as he drifted in-field from the left setting the tone. Oscar hesitated when his team needed a tackle. Kane merely skimmed his shot into the corner from 20 yards and, instantly, parity stoked the hosts’ conviction.

Their second was neatly conjured, the busy Christian Eriksen scuttling forward with Chelsea becalmed to liberate Chadli behind Gary Cahill. Courtois charged to the edge of his area to intercept but the Belgian's shot was poked beyond the goalkeeper and on to the far post, with Rose bravely bursting on to the loose ball to belt in a first league goal here since that derby winner on debut against Arsenal in April 2010. He was bruised while converting, though not as wounded as the visitors. Chelsea were still wheezing in disbelief when Cahill upended Kane as the striker appeared on his blindside. Andros Townsend, the third youth-team graduate turned goalscorer, thumped in the resultant penalty.

Mourinho's response was to fling on Ramires for Oscar – who had been unwell of late and appeared off the pace with defensive duties – but his team's rearguard were shellshocked, their composure drained. Nemanja Matic has not been exposed to this extent since returning to London from Benfica. Cahill has snuffed out the threat of Lionel Messi and Luis Suárez over the years, but Kane was leaving him dazed and confused. When Chadli pinned back Branislav Ivanovic and shifted possession inside to Kane, the young English forward turned Matic far too easily and curled a fourth through John Terry's legs with Courtois helpless.

This had become a humiliation though Hazard’s instant reply, seizing upon Federico Fazio’s error before exchanging passes with Fabregas and using the space permitted him by Vertonghen to convert in the corner, offered hope of recovery.

Lloris did well to deny Cesar Azpilicueta in the frenetic pressure which followed, and Terry would convert a third from close range before the end, but Spurs were basking in five of their own by then. Everything they struck seemed to fly in with Chadli's last, deflecting slightly off the visitors' captain, maintaining the trend.

(Guardian service)