A tired Andy Murray paid the price for his unexpected success on clay by withdrawing from the Italian Open.
The world number three had made it 10 wins in a row on Wednesday with a straight-sets victory over Frenchman Jeremy Chardy that put him into the last 16 in Rome.
That followed his first back-to-back ATP Tour titles on clay in Munich and Madrid, where he gained an impressive victory over Rafael Nadal on Sunday which hinted at a strong run in the forthcoming French Open.
The two-time Slam winner was due to play Belgium's David Goffin for a place in the quarter-finals but his impressive run came to an abrupt end when he announced before the scheduled start that he was pulling out due to fatigue.
Murray said he felt "pretty exhausted" after practising for 40 minutes on Thursday morning.
"I'm very tired just now and I need to take a break," said Murray, who only confirmed his participation in the Italian Open on Sunday.
"I didn't expect to do what I've done the past few weeks. My body has never been through that before on the clay. It's a surface I've always struggled on physically. My body's always found the surface difficult. This year, it's been very good.
"I also don't want to risk making it worse; in the past, I've maybe trained too much. I wanted to play in this event. It's a big tournament, a lot of points on offer. The time of year is tough on everyone and it's just one of those things.
"There's no long-term injuries to worry about. Things are a little bit stiff and sore because of the amount of matches I've played.
"It wasn't just about today's match. It was about the rest of the tournament... and further down the line the possibility of getting sick and missing five, six or seven days."
Murray, went into the clay-court season on the back of just a week's practice in Barcelona and admitted on Wednesday that his recent schedule was beginning to take its toll, saying: "My legs were a bit tired at the beginning."
The French Open starts in Paris on May 24.
Murray added: "I'm going to take a few days' rest. I won't train; I won't go on the court. I just need a few days to recover.
"I'll go home either tonight or tomorrow morning and spend a few days at home, maybe see my physio a little bit over the weekend to try and help the recovery process.
"I'll try to rest and sleep and recover; that's what I need to do right now. Hopefully I'll get to Paris early next week and get some good days' training done there."