Salomon Kalou snatched a late winner as Chelsea fought back from a goal down to beat Tottenham 2-1 and pick up a vital three points.

The London derby looked on course to end in stalemate until the substitute popped up in the 89th minute to bundle the ball home as Chelsea surged forward in numbers.

Carlo Ancelotti's men can consider themselves fortunate after an error from the officials gifted the home side an equaliser.

The first half ended in controversy after a 35-yard shot from Frank Lampard squirmed through the legs of Spurs keeper Heurelho Gomes.

Despite the whole of the ball failing to cross the line the goal was awarded on the advice of the assistant referee, sparking angry protests from the Tottenham players.

Spurs took the lead in the first half with a bolt from the blue as Sandro rifled home a shot from range to put the visitors ahead.

In the second period Tottenham soaked up Chelsea pressure who felt aggrieved to not receive a penalty after Younes Kaboul felled Florent Malouda in the box, however all was forgotten as Kalou later made sure of three points.

High stakes

The visitors, who needed to win to stay in the hunt for a top-four spot, looked like holding on for a draw that was no good to either side until substitute Kalou fired home in the 89th minute from an offside position, with Martin Yerby failing to raise his flag.

The watching Sir Alex Ferguson, who left 15 minutes from time, would not have been amused about the champions being gifted the most controversial of victories that put the pressure back on his United side.

The big question before the game was whether Ancelotti would put Chelsea's title hopes at risk by pairing Fernando Torres and Didier Drogba in attack.

Despite his last gamble of starting Torres in the Champions League defeat to United backfiring spectacularly, Ancelotti took a chance again.

He did play it safe with the system, retaining the 4-3-3 that had been key to the Blues still being in the championship reckoning.

But that meant Drogba playing on the right, a move that produced mixed results.

Chances

Torres' long-awaited first goal for the club had an obvious effect on the Spaniard's confidence but he never really had a sniff in the first half.

Drogba was also more subdued than of late but he almost opened the scoring with a blockbuster 35-yard free-kick that crashed off the crossbar.

Michael Essien - declared fit despite hobbling off against West Ham last week - and the in-form Florent Malouda also went close.

Otherwise, Spurs belied their recent form of one win in 10 and their miserable record at Stamford Bridge to give as good as they got, Roman Pavlyuchenko dragging wide after a Branislav Ivanovic slip.

But no one could have predicted the manner or scorer of their opening goal.

Sandro was bought as a defensive midfielder but there was nothing defensive about the touch and 30-yard half-volley that thundered through the fingertips of Petr Cech after 19 minutes.

The Brazilian instinctively ran to manager Harry Redknapp to celebrate only to receive a monumental telling off.

Goal threat

Chelsea piled on the pressure, going too far at times, with Ivanovic booked and captain John Terry lucky to escape yellow on his 500th appearance for the club.

They should have levelled when Gomes tipped over Essien's header and the resulting corner saw Drogba flick the ball on for Torres, who stooped to nod over when he should have used his foot.

Sandro produced an excellent tackle on Lampard to deny him what looked a certain equaliser before all Tottenham's good work was undone on the stroke of half-time by Gomes' latest howler and an even bigger blunder by Cairns.

Gomes took no chances after the break when he parried a 25-yard shot from Drogba, who was then booked for foolishly refusing to give the ball to the referee.

With just under half and hour for his side to rescue his title bid, Ancelotti finally abandoned the Torres-Drogba experiment and restored Kalou to his attack.

Kalou's first touch was almost a goal as another Gomes blunder saw him punch Drogba's 40-yard free-kick straight at the striker, who had no time to react.

Chelsea screamed for a penalty when Kaboul brought down Malouda and the home side's attacks became increasingly frantic, while there was always the danger of being hit on the break.

Terry scuffed a disguised Drogba free-kick straight at Gomes before Chelsea's pressure finally told, with Drogba's shot deflecting to Kalou to stab home.

Spurs pushed in vain for an equaliser and Gomes understandably had words with referee Andre Marriner as the players left the field.

Chelsea	Team Statistics	Tottenham Hotspur
2	Goals	1
1	1st Half Goals	1
10	Shots on Target	1
6	Shots off Target	5
4	Blocked Shots	7
6	Corners	5
12	Fouls	14
0	Offsides	0
3	Yellow Cards	1
0	Red Cards	0
85.7	Passing Success	84.8
34	Tackles	32
76.5	Tackles Success	68.8
53.1	Possession	46.9
61	Territorial Advantage	39

Click Here For Official Team Sheet

Teams 

Chelsea  Cech, Ivanovic, Luiz, Terry, Cole, Essien (Ramires 57), Mikel, Lampard, Malouda (Anelka 73), Drogba, Torres (Kalou 62)
Subs Not Used  Turnbull, Alex, Zhirkov, Benayoun
Booked  Ivanovic, Drogba, Terry
Goals  Lampard 45, Kalou 89

Tottenham Hotspur  Gomes, Kaboul, Dawson, Gallas, Corluka Pienaar 78), Lennon, Sandro, Modric, Bale, Van der Vaart (Jenas 85), Pavlyuchenko (Defoe 58)
Subs Not Used  Cudicini, Bassong, Rose, Crouch
Booked  Pavlyuchenko
Goals  Sandro 19

Attendance  41,681

Referee  A. Mariner