Costa has hamstring injury and went to hospital with an illness

Diego Costa has a 'chance' to play, but Loic Remy will not play

Blues boss Jose Mourinho says the players are 'ready and confident'

Jose Mourinho is refusing to rule Diego Costa out of Sunday's crunch clash against Manchester United.

The Spain centre forward has missed the last two games with a hamstring problem and was even admitted to hospital this week with a virus.

But Mourinho, who confirmed Loic Remy would miss the next three weeks with a groin problem, says his star striker has a chance of making the visit to Old Trafford.

VIDEO Scroll down to watch Jose Mourinho say Costa has a 'little chance' to play

Diego Costa has a 'chance' of facing Manchester United at Old Trafford, insists Chelsea boss Jose Mourinho

Loic Remy scored the opener against Maribor on Tuesday night but will not be fit for the trip to United

Chelsea boss Mourinho is confident that his side will be ready to face up to the challenge at Old Trafford

Remy limped off after injuring his groin and his injury will keep him out for two to three weeks

When asked on Friday if Costa would play, Mourinho said: 'There is a chance, he has a little chance. Diego has a little chance, the same as Ramires and (John Obi) Mikel.

'But Remy is out - he will not play. He has no chance.

'Everything happened (to Costa). He was obviously injured - that was hamstring. He had to go to hospital with a viral situation that we didn't manage to resolve without being in hospital over one night - that was before Maribor.

'Against Maribor he wouldn't have been ready from the injury, no chance. But being ill didn't help the recovery process because we didn't have him at Cobham (training ground). Medical staff had to go to his house because we didn't want to bring him here with a viral situation.

'He trained individually, not yet with us.'

Didier Drogba, meanwhile, has had no reaction to his 75 minutes against Maribor in the Champions League and could play. Mourinho also confirmed that Thibaut Courtois will get the nod in goal.

Didier Drogba, in action against Maribor on Tuesday, is operating at less than 100 per cent right now

Oscar (right) gave Chelsea an early lead against Crystal Palace last week by scoring a wonderful free-kick

Fabregas doubled Chelsea's lead at Selhurst Park early in the second half last weekend

The Blues are unbeaten in the Premier League - having won seven and drawn one of their eight matches so far - and the Portuguese believes his squad are confident heading up to the North West for Sunday's tie.

He was quick, however, to insist his team 'share nothing' with Arsene Wenger's Arsenal Invincibles side of 2003-04 despite comparisons.

'We are playing well, we are confident, top of the league and in a good position to qualify for the Champions League. The camp is happy and we are ready for the game,' he continued.

'I only have positive news!'

Mourinho says his side are focused ahead of trip to Old Trafford but will give United the respect they deserve

Mourinho will go head-to-head with his former boss Louis van Gaal at Old Trafford but he is concentrating on picking up the three points.

He said: 'I like to go to Old Trafford and I like to play there. I've been there with Porto, Inter (Milan), Real Madrid and Chelsea and I like to go there and play there..

'Louis van Gaal was important. He gave me a good opportunity to work at a high level, as a young coach to be working four consecutive years, one with Mr (Bobby) Robson and three with Louis in a club like Barcelona is very important.

'If I had to choose important people in my career for sure he's one.

Cesar Azpilicueta (bottom) will not feature for Chelsea after being sent off against Crystal Palace last week

Oscar (far left) is congratulated by his Chelsea team-mates for his brilliant dead ball strike against Palace

And Mourinho believes his side will show United the respect they deserve, but they will not go there scared.

Chelsea's wonderful start to the season gives them some momentum.

He said: 'We will respect one of the best and most difficult opponents in the league, but we're confident and in a good moment and situation. There's no reason to change our positive feeling.

'We play a big team, yes, but we're in a good moment and going to discuss the points and try the best result.

'But we are not going to Old Trafford to get a point - we are heading there to win.

'I want to fight for three points but sometimes during a game a point is a positive result.'

Mourinho (right) and Warnock before last week's game - but the latter was not happy with some decisions

Interestingly, Mourinho also claimed he does not see former Chelsea midfielder Juan Mata as a 'special player'.

Mata was sold to United in January by Mourinho and he believes although the Spaniard did a 'good job' for Chelsea, he was not a 'special player'.

'For me Juan is a very good player and I look at him as a very good player. I don't look at him as a special player because of certain circumstances.

'Because if I did there would have been 20, 30, 40 players who we sold or decided to leave. It happens. For me not a problem.

'He a very good player and very good players are dangerous. Relations are good.'