Jose Mourinho has revealed that Diego Costa will be fit to face Sunderland on Saturday despite picking up a 'knock' during Chelsea's 5-0 win against Schalke.

Despite not being able to find the net in Germany, Costa put in another impressive display before being replaced by Blues veteran Didier Drogba in the 66th minute.

Mourinho has rarely been able to use Costa for more than one game a week due to various muscle complaints, but the striker seems to have had enough time to recover after being left out of Spain squad for the most recent international break.

Diego Costa will be fit to face Sunderland on Saturday, claims Chelsea boss Jose Mourinho

Costa was substituted in the 66th minute after picking up a slight leg injury

The Chelsea boss said: 'He (Costa) took a knock. In his leg, I don't know (what it was exactly). I wasn't so worried at the time. He will be ready for Saturday.'

The Group G clash saw the Blues secure first spot and qualify for the last 16 with a dominant performance in Gelsenkirchen thanks to goals from John Terry, Willian, Didier Drogba and Ramires.

Mourinho also believes his side are playing with such confidence that it's almost impossible for them to feel tired.

Chelsea qualified for the Champions League last 16 with an impressive 5-0 win against Schalke

He added: 'When the team are playing the way we are, the players don't get tired.

'You have such control of the game, the ball does the running. The players are not chasing opponents in control. Playing the way we are is a pleasure for the players.

'Fabregas said he enjoyed the West Brom game so much, but today I think they enjoyed it even more. The players feel very responsible, but they are enjoying it very much.'