Postpublished at 44 mins
Chelsea 2-0 Tottenham
Good cross from Romelu Lukaku that is not fully cleared and Cesar Azpilicueta fancies a pop, which is closed down. Chelsea enjoying almost all off the ball at Stamford Bridge.
Use play icon at top of page to listen to live commentary from BBC Radio 5 Live
Spurs give ball away and Havertz shot deflects off Sanchez on the way in, comical own goal for second
Lukaku returns to Chelsea XI after apologising for comments in an interview
Second leg takes place on 12 January
Arsenal face Liverpool in other semi-final - first leg moved to 13 Jan
Final on 27 February
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Alex Bysouth
Chelsea 2-0 Tottenham
Good cross from Romelu Lukaku that is not fully cleared and Cesar Azpilicueta fancies a pop, which is closed down. Chelsea enjoying almost all off the ball at Stamford Bridge.
Chelsea 2-0 Tottenham
That was the chance for Romelu Lukaku!
Hakim Ziyech saunters inside and picks out an unmarked Romelu Lukaku, but he can only head wide of the far post.
Chelsea 2-0 Tottenham
That might be the first time Kepa has had to make a save.
It's Tottenham's best move of the match. Davinson Sanchez breaks up play and finds Son Heung-min, who spreads it to Emerson Royal.
The wing-back's cross finds Matt Doherty and he can only head into the air, with Kepa just about getting there under pressure from Lucas Moura.
Chelsea 2-0 Tottenham
Chelsea have dominated, but both goals have been awful errors from Tottenham.
The visitors have done nothing to suggest they can get back into this one either.
Chelsea 2-0 Tottenham
Karen Carney
Former Chelsea midfielder on BBC Radio 5 Live
Horror. There's no Chelsea player around either of them. Ziyech whips in the free-kick. Tanganga is on the six-yard line and heads it on Ben Davies, who has no idea what's going on.
It's such an unorthodox goal. There's nothing Davies or Lloris can do about it and Tanganga was just doing his job. It's a hash of a goal to concede. They all could have left it and it would have been dealt with.
Ben Davies OG (34 mins)
Nightmare for Spurs!
Japhet Tanganga attempts to head clear from the free-kick but can only nod straight into his own team-mate, and the ball deflects off Ben Davies and beyond a helpless Hugo Lloris into the net.
Antonio Conte will be fuming.
Chelsea 1-0 Tottenham
Tottenham are giving it away far too casually in attack. A poor pass from Matt Doherty allows Chelsea to break and Davinson Sanchez ends up bringing down Romelu Lukaku.
Chelsea 1-0 Tottenham
A Chelsea corner comes all the way through to Antonio Rudiger, but he can't quite work it back into the danger zone.
Chelsea 1-0 Tottenham
Just four touches for Romelu Lukaku in the opening half an hour.
Chelsea have had loads of the ball, but their returning forward hasn't seen much of it.
Chelsea 1-0 Tottenham
Hakim Ziyech was supposedly starting as a right-wing back tonight, but he's popping up all over the place, whipping a cross in from the left this time.
Chelsea 1-0 Tottenham
Tottenham's Brazilians team up to win the ball off Marcos Alonso, with Lucas Moura and then Emerson Royal putting a foot in.
Chelsea still have it though, and Hugo Lloris comes flying out to punch clear a cross from the right.
Chelsea 1-0 Tottenham
Chelsea clear. And they can break!
Romelu Lukaku takes it on, heading out to the right, but the forward overruns it and slips slightly as the ball runs out for a Spurs throw.
Chelsea 1-0 Tottenham
First chance for Spurs to get down the right and cross and Son Heung-min's attempted delivery is blocked by Saul. The visitors get a corner.
Chelsea 1-0 Tottenham
Mason Mount chases a long pass, hair bobbing up and down like a sixth form prefect, but he won't reach that.
Tottenham look to break and again it is Matt Doherty popping up on the left, but there are plenty of blue shirts back quickly to cover.
Chelsea 1-0 Tottenham
Karen Carney
Former Chelsea midfielder on BBC Radio 5 Live
There's not one Chelsea player in the middle. They're playing on the outside. There's a massive gap in the central corridor. They're trying to make Spurs run and pulling them from left to right.
Chelsea 1-0 Tottenham
A chance for Tottenham to get forward down the left with Matt Doherty, before switching play to Emerson Royal on the right. That's probably the longest Spurs have had the ball in a while, only for the attack to fizzle out as a pass runs through to Kepa in the Chelsea goal.
Chelsea 1-0 Tottenham
Oooh. Hakim Ziyech is in the mood. He wriggles on to his left foot and looks to whip one, but it curls over the crossbar.
Chelsea 1-0 Tottenham
Tottenham deal with the corner and then force Chelsea back into their own half. Antonio Conte's side can't get on the ball, though.
Chelsea 1-0 Tottenham
Neat footwork from Hakim Ziyech and he finds Mason Mount, whose effort is closed down quickly.
Corner for Chelsea.
Chelsea 1-0 Tottenham
Almost another clanger from Spurs!
Pierre-Emile Hojbjerg hacks a clearance straight at Oliver Skipp and it bounces into Kai Havertz's path.
He only has Hugo Lloris to beat from the angle, but takes it first time and scuffs an effort towards the near post that the goalkeeper gets down easily to save.