Jose Mourinho: Costa CAN'T play three matches in a week..

Jose Mourinho has admitted he cannot afford to take a risk on Diego Costa after his gamble on Didier Drogba backfired.

Mourinho handed the Ivory Coast veteran the first start of his second Chelsea spell but watched as the 36-year-old missed three great chances as his Blues dropped two Champions League points.

Klaas-Jan Huntelaar's second half strike punished the hosts' misses after Cesc Fabregas put them in front, ending their 100 per cent start to the season.

But while Mourinho sent on seven-goal Costa for the final 18 minutes, he revealed the Spain striker's hamstring problems are a major concern.

Mourinho said: ''Costa has a problem and he can't play three matches in a week.

''If he has one week to let the muscle recover, he can start but three days, after Saturday, is not enough.

"It [starting with Drogba instead] was not to protect him for the game at City on Sunday, but now we have a problem and now we have to resolve it as best we can.

''He was not in condition to play. If he had started, he would not have been able to play on Sunday. We have to manage the situation until the moment he's completely fine but I don't know how long that will be. We have to go step by step.''

Mourinho added: ''It is frustrating because we did everything to win and we didn't.

''We had very good chances to score the second goal and didn't take them, although when they equalised we had fantastic reaction and chances to win the game.

''But that's football. That's the Champions League. That's normal. In a short competition, we dropped two points.''

Source: Mirror Sport