Jose Mourinho admits he doesn’t know if Diego Costa will be fit for Chelsea opener

Chelsea manager Jose Mourinho does not know whether Diego Costa will be fit when the Barclays Premier League champions begin their title defence at home to Swansea on Saturday.

Costa missed last Sunday's Community Shield loss to Arsenal with a recurrence of the hamstring problem which has persistently plagued him in recent seasons.

Radamel Falcao and Loic Remy are vying for the starting spot if Costa is unavailable, and Chelsea have no further concerns.

"I don't know. I promise you, I don't know," Mourinho said.

"I think he's going to train with the team [on Friday evening].

"His reaction after that and his decision to be confident to play is another story."

Mourinho dismissed the suggestion Chelsea might need to buy another striker due to Costa being an ongoing fitness concern.

"Three is the perfect number and we have three," said Mourinho, who is prepared to field Loic Remy or Radamel Falcao against the Swans.

Put to him he has only two and a half strikers due to the uncertainty surrounding Costa, Mourinho said: "The half when he plays is one and a half, so [that] compensates, because he's a fantastic player.

"I cannot say I don't need him. He's such an important player for us.

"Not just for the goals he scores, but also for the football he produces and also for the mentality he helps to create in the team."