Atletico Madrid's Diego Costa doubtful for Barcelona clash

Atletico Madrid faced an anxious wait to see whether key striker Diego Costa would be fit to play in his side's Champions League quarter-final, first leg clash away to Barcelona on Tuesday after he left training early with an apparent knee injury. (Preview)

The 25-year-old Spanish international walked off the Camp Nou pitch after just five minutes of his side's training session on Monday and Atletico boss Diego Simeone admitted it will be a race against time to get his top scorer fit.

"We have to wait until tomorrow. I have spoken with the doctor and we will evaluate it tonight and during the day tomorrow and we will see because there are still a lot of hours to go," he told Television Espanola.

"I don't know (if he will play tomorrow), first we have to talk with the doctor to see what condition he is in and then we will take a decision.

"In theory, leaving the training session today, I think it will be difficult for tomorrow."

Costa has been in great form in recent weeks, scoring six times in five games as Atletico have moved back to the top of La Liga and progressed to the last eight of the Champions League for the first time in 17 years.