Newly-crowned French Open champion Rafael Nadal lost in the first round of the Halle Open to Germany's Alexander Waske as the Spanish teenager made an unhappy transition from clay to grass on Wednesday.
Nadal, who arrived in Germany on Monday evening and had only one day to prepare for the match, lost 4-6 7-5 6-3.
It was the 19-year-old's first defeat in 26 matches and he said the contest had been a vastly different experience to his triumph on the clay at Roland Garros.
"Today was totally different, no? He served well and I could not play my best tennis on grass within these couple of days," he said.
The Mallorcan had looked fresh and energetic in winning the first set at the pre-Wimbledon event, playing some aggressive drives as well as delicate volleys, drop shots and lobs and was much too strong for an error-prone Waske.
But the unfancied German, who has played only two ATP tournaments this year, losing both times in his first match, came back strongly to take the next two sets.
"Rafael Nadal has just turned 19 and I think he has a great future ahead of him," Waske said. "He will definitely be giving spectators a lot of pleasure in the years to come."
If Nadal had reached the semi-finals of the Halle event, he could have faced world number one Roger Federer of Switzerland, who he beat in the French Open at the same stage.
Later on Wednesday Nadal was due to face Waske again, this time in the doubles, with Spanish compatriot Feliciano Lopez.
Second seed Marat Safin had to save a match point before reaching the quarter-finals on Wednesday when a leg injury forced Fabrice Santoro to retire.
Safin, himself struggling with a knee problem, lost the first set 6-3 to the Frenchman who had beaten the Australian Open champion in seven of their previous eight meetings.
The Russian saved a match point in the tiebreak before winning it 9-7 and broke Santoro in the third to go 3-2 up before his opponent was forced out of the pre-Wimbledon grasscourt event.
Safin will play Belgium's Olivier Rochus in the quarters.