Roger Federer added another win to his already burgeoning clay-court record this season.

Federer improved to 16-3 on clay in 2008 by beating Sam Querrey of the United States 6-4, 6-4, 6-3 Monday in the first round of the French Open, where he is trying to become only the sixth man to complete a career Grand Slam.

"I've played well all clay-court season long," said the top-ranked Federer, who is 27-7 overall this year. "Didn't have many hiccups really, and I have plenty of matches. That was my goal as well."

Federer came into the French Open with only one title this year, which he won on clay. His seven losses are more than he had for the entire season in 2004, '05 and '06.

On Tuesday, the start of play was delayed by rain for 2 hours, 50 minutes. Rafael Nadal was scheduled to begin his quest for a fourth straight French Open title against Thomaz Bellucci of Brazil. Nikolay Davydenko, Lleyton Hewitt and 2003 champion Juan Carlos Ferrero were also to play.

Maria Sharapova and Amelie Mauresmo were to play in the women's tournament.

Federer was broken once early in the first set Monday, but he managed to win five times on Querrey's serve.