Roddick has not been beyond the third round in six attempts in Paris

The American fifth seed was trailing 6-4 7-5 1-0 to the Spaniard when the left ankle injury he suffered last week became too painful to continue.

However, Lleyton Hewitt, who is also recovering from an ankle injury, overcame a sluggish start to beat Czech Jan Hernych 7-6 (7-5) 3-6 6-2 6-0.

The Australian, seeded 14, next plays French wildcard Mathieu Montcourt.

Roddick, who has never got beyond the third round in six attempts, admitted he was wrong to even attempt to play in the tournament.

He picked up his ankle injury at last week's World Team Cup in Dusseldorf and said: "It was a lost cause out there.

"I think I was being stupidly optimistic. It was never going to be 100% here. I haven't had much practice time.

"It was only getting worse and I wanted to avoid something huge. If I rolled the ankle again, who knows how long I would have been out?"

Elswheer, Chile's Fernando Gonzalez won the battle of the big hitters against former world number one Marat Safin 6-3 1-6 6-3 6-1.

The ninth seed, who reached the quarter-finals at Roland Garros in 2003, had too much claycourt nous for the Russian.

Safin returned to the tour in February after eight months out with a knee injury and as a result the twice former grand slam winner is ranked only 53, meaning he was unseeded.

Tommy Haas marched into the second round with a 6-4 6-3 6-3 victory over Rainer Schuettler in an all-German clash.

Albert Montanes caused a minor upset by beating 17th seed Robby Ginepri 6-3 6-7 6-1 6-4.