Clay falls from Andy Murray of Britain's shoes as he serves to Juan Ignacio Chela of Argentina during their quarter-final match at the French Open tennis tournament at the Roland Garros stadium in Paris June 1, 2011. [Photo/Agencies]

Against Chela, Murray said his ankle didn't bother him too much, giving him some confidence ahead of Friday's match against Nadal.

Related readings: Murray fitness under scrutiny as quarters beckon  Mixed bag from Murray at Roland Garros

"I've got two days to rest up, recover, and get ready for Rafa, which is always one of the most exciting matches for me on the tour," Murray said. "I'm glad I've got tomorrow off where I can rest and recover. It does make a big difference. Forty-eight hours are enough to recover and calm myself down and take everything in and go from there."

On a windy Court Suzanne Lenglen, Chela broke twice to open a 4-1 lead with a forehand passing shot straight at Murray, who struggled physically and even looked out of breathe after long rallies.

But Murray saved two set points at 5-3, the second with a backhand drop shot. He then broke to level the score at 5-5 with a forehand winner and won five points in a row in the tiebreaker.

"Then I got up in the second (set), sort of maybe lost concentration a little bit, which you can't afford to do against someone like Juan, who has a lot of experience on this surface," Murray said. "Something I definitely won't get away with against Rafa."

Chela said Murray didn't seem diminished at all by his ankle injury.

"If he was really injured, I don't believe he would have been able to run that much," the Argentine said. "We played three hours, and I didn't notice he had any difficulty in running."

Murray is only the second British man in the Open era to reach the French Open semifinals after Tim Henman seven years ago. If he reaches the final, he would be the first Brit in the championship match at Roland Garros since Bunny Austin in 1937.

"Tactically I'm going to have to be very good," Murray said. "So I can definitely win. I just need to play my best."