Chelsea made it a day of misery for former manager Andre Villas-Boas as they stayed top of the Premier League with victory in an enthralling encounter at White Hart Lane.
Tottenham boss Villas-Boas was facing Chelsea for the first time since he was sacked in March after only nine months in charge - and for a brief spell in the second half it looked like he would celebrate with three points.
Chelsea, without captain John Terry as he started a four-match ban for racially abusing QPR's Anton Ferdinand, led at half-time through Gary Cahill's magnificent volley.

Spurs, however, reversed fortunes dramatically at the start of the second half with two quick goals from William Gallas and Jermain Defoe.
It was a situation that called for Chelsea to show the substance to match the style this reshaped side is offering up this season. They delivered both to secure a hugely impressive win.
The outstanding Juan Mata struck twice in three minutes as Chelsea regained the ascendancy and substitute Daniel Sturridge's simple fourth in stoppage time completed a hugely satisfying performance from the Champions League holders.
Spurs were forced into a late change when Gareth Bale dropped out of their starting line-up after his partner went into labour - and it was understandable that they should miss a player of his influence.
Nothing, however, can diminish the growing sense that even though this Chelsea team is undergoing something of a transition, they have the quality to be very serious contenders for the title this season.
And, in Mata, they have a player of the highest quality as a creator and scorer who was able to cast his spell over this wonderful game.
Gallas, who endured a miserable day defensively, wasted a perfect opportunity to give Spurs the lead after only three minutes when he failed to make firm contact with Gylfi Sigurdsson's free-kick from six yards.