Aguero and Fernadinho sent off late on - tackle sparks scuffle with multiple players
Willian and Hazard score on the break as Blues fight back
Costa drilled in the equaliser from Fabregas assist
De Bruyne missed open goal from three yards shortly before Chelsea leveller
Cahill diverted Navas cross into his own net for the opener
Man City 1-1 Chelsea
Phil McNulty
BBC Sport chief football writer at Etihad Stadium
No wonder Pep Guardiola forget the risk his expensive suit by crashing to his knees after Kevin De Bruyne's dreadful miss - he knows games as tight as this are decided on the finest margins.
And just in case he didn't know, Chelsea now have a renewed spring in their step after Diego Costa's equaliser. This game is wide open now.
Man City 1-1 Chelsea
Here is that Chelsea goal in graphical form. Obviously it doesn't do justice to Cesc Fabregas's long raking pass (number four), or Diego Costa's excellent first touch (number 19) to create the space for the shot.
Other people involved in the build-up were David Luiz (30), Thibaut Courtois (13) and Cesar Azpilicueta (28).
Image source, OptaMan City 1-1 Chelsea
Chelsea are well on top here now. Manchester City are riding out a storm.
Man City 1-1 Chelsea
Dan Graham: And people say LFC can't defend. Laughable from both sides
Vieira: That's what you call a Fabrepass to a Diegoal...
Man City 1-1 Chelsea
Chris Waddle
Ex-England winger, BBC Radio 5 live at Etihad Stadium
Willian's done well since he's come on and Diego Costa has sprung to life. He has been very lively in the second half, causing all sorts of problems.
Image source, ReutersMan City 1-1 Chelsea
Diego Costa 1, Sergio Aguero 0. Chelsea's top scorer is winning the battle between the Premier League's top scorers.
Another chance for Aguero, another decent save from Thibaut Courtois.
Man City 1-1 Chelsea
The game has turned on that Kevin de Bruyne miss. That came just four minutes before Diego Costa's leveller. We've got a cracker on our hands, ladies and gentleman. Don't go anywhere...
Image source, Getty Images
Diego Costa
What were we saying?! Diego Costa comes to life - and Manchester City are punished for their profligacy.
Cesc Fabregas picks out the Blues top scorer, who bullies Nicolas Otamendi before smashing in the equaliser. Game on!
Image source, ReutersMan City 1-0 Chelsea
Not Diego Costa's day is this. Doesn't look like scoring today...
One shot from the Chelsea top scorer. And that was rubbish. Now a heavy touch sees another chance go begging.
Image source, OptaMan City 1-0 Chelsea
Chris Waddle
Ex-England winger, BBC Radio 5 live at Etihad Stadium
I don't know how Kevin De Bruyne managed to hit the crossbar there! Great cross from Jesus Navas and De Bruyne wrapped his foot around it, but he lifted it up, against the top of the bar and away. But that was an open goal, two or three yards from the goal.
To be honest, Chelsea aren't really impressing. I thought the visitors would have been asking more questions after the break, but they're sitting back and seem off the pace.
Image source, ReutersMan City 1-0 Chelsea
How. Has. He. Missed.
Kevin de Bruyne clatters the crossbar from all of three yards. Another great cross into the danger zone by Jesus Navas cleans out the Chelsea defence.
City should be out of sight by now.
Image source, ReutersMan City 1-0 Chelsea
Slight concern for Manchester City as Sergio Aguero goes down with a knock. Wait... he's back on his feet.
Image source, ReutersMan City 1-0 Chelsea
Josh Hammond: If Cahill had done that at the other end we'd be talking about that goal for weeks!
Lifa Nati: Fabregas is a total passenger in this game and should be rightly substituted.
Man City 1-0 Chelsea
Chris Waddle
Ex-England winger, BBC Radio 5 live at Etihad Stadium
What are Gary Cahill and Thibaut Courtois thinking about there? I have no idea.
Sergio Aguero did in fact have two players he could have squared the ball to for an easier finish, but at that exact moment you don't think about that if you're a goalscorer.
Man City 1-0 Chelsea
What are you doing?! Gary Cahill almost has another 'mare, falling to sleep as Sergio Aguero mugs him of the ball.
Marcos Alonso's backpass is poor, but Cahill has no awareness of Aguero as he tries to shepherd the ball back to Thibaut Courtois.
Cahill redeems himself by blocking Aguero's goal-bound strike with a lunging slide.
Image source, ReutersMan City 1-0 Chelsea
Pedro's day is done. Willian's turn as Chelsea make their first substitution.
Image source, ReutersMan City 1-0 Chelsea
Got to do better Diego! Chelsea striker Diego Costa muscles his way into space on the right side of the City box, but shanks his shot wide into the side-netting. Got to go across the keeper.
Image source, ReutersMan City 1-0 Chelsea
In the build-up to that City chance, Ngolo Kante absolutely crunched David Silva with a crude challenge. Anthony Taylor goes back to book the Chelsea midfielder.
Man City 1-0 Chelsea
Leroy Sane shows why Manchester City paid £37m for him. The young German shows his studs to Cesar Azpilicueta, racing away from the Chelsea defender in a central position. He slips a perfectly-weighted pass to Kevin de Bruyne whose daisy-cutting shot is saved by Thibaut Courtois's legs.
Man City 1-0 Chelsea
Route one. David Luiz goes all Peter Kay, lumping the ball forward. Pedro is on the chase like a hungry springer spaniel, but the ball just evade his boot and goes into Claudio Bravo's hands.