Roger Federer at Madison Square Garden in New York City on March 10, 2008. (UPI Photo/John Angelillo)

The third grand slam event this season starts Sunday on the clay courts of Roland Garros.

Federer, 26, told the Mail and Guardian newspaper Thursday he knows that in his 10th attempt to win the French he likely will have to beat clay-court specialist and world No. 2 Rafael Nadal of Spain.

"I'm pushing Rafa and I have the feeling I can beat him if I play the right way," Federer told the newspaper. "I feel like my defensive skills (on clay) are getting better and better."

Federer's clay-court record against Nadal is 1-8 -- and 5-2 on all other surfaces -- and last week, the Spaniard became only the third player since 1990 to win the three ATP Masters Series titles on clay -- Monte Carlo, Rome and Hamburg -- joining Gustavo Kuerten and Marcelo Rios.