Andy Murray slumped to a disappointing 6-4 6-7 5-7 defeat against local favourite Jean-Rene Lisnard in the first round of the Monte Carlo Masters.
Murray was playing his first match since splitting with his coach
The British number one won the first set but lost the next two as leg cramps brought him to a virtual standstill.
The Scot later recovered to partner Tim Henman in the doubles against Tomas Berdych and Jarkko Nieminen.
The British duo advanced to round two after their opponents retired when trailing 3-2 in the first set.
Murray was making his first appearance since ending his 10-month partnership with coach Mark Petchey.
The Dunblane teenager, who was recovering from a virus as well as an ankle injury suffered in Miami, later blamed a lack of match practice for his first-round exit to Lisnard.
"I knew I wasn't 100% fit coming into the match, I had very little time to practice because of the ankle injury and then the sickness," said Murray.
"I just don't understand why I get cramp because I don't feel tired at all. Going on to play, I didn't feel `I don't want to go out there'.
"I felt fine enough to play. But when your legs cramp, you just can't do anything. I don't quite know what it is.
"Obviously, this is my first match on clay, so I wasn't expecting to play great and feel great on the court.
"But I had a lot of chances to win the match."
Murray looked set for victory after winning the first set and opening up a 3-1 lead in the second.
Some scrappy play allowed Lisnard to hit back, the 26-year-old Monegasque, ranked more than 100 places below Murray, squaring the match by winning the tie-break 7-5.
Murray's fitness then disintegrated rapidly, although he briefly led 4-2 in the deciding set before losing it 6-4.