Paul Merson's looks ahead to this weekend's big head-to-head and reckons the outcome revolves around one man...

Chelsea need to change how they play if they want to get a result at Man City. If they go out and play Nemanja Matic and Cesc Fabregas as the two central midfielders then they'll get run ragged because Fabregas isn't disciplined enough in a game like this. Ramires or John Obi Mikel need to come in and sit with Matic and do a job or else City will cause havoc. 

I think Jose Mourinho will change things and won't play like he did against Everton, Swansea and Schalke. As long as he tightens things up they can get a draw.

Mourinho has suggested Diego Costa won't play and if that happens then Man City will win, it's as simple as that. He's not going to play him in the Capital One Cup so I've no doubt he will play in this one though.

As for Man City, they didn't have enough pace on the break against Bayern Munich and it was only a matter of time before they conceded to a top team. I think City will get a result - but what the result is all depends on whether Costa plays or not.

PAUL PREDICTS: 1-1 if Costa plays, otherwise 2-0 to Man City