PARIS — For all of Roger Federer's titles at Wimbledon, the U.S. Open and the Australian Open — and there are 10, and counting — his career very well may be defined eventually by how he fared at the French Open.

Federer is well aware of that. It's why he tweaked his schedule and his practice routine in the months before heading to Paris. It's why he ratcheted up his commitment to fitness training, knowing what a grind playing on red clay can be.

"There's more focus on the French Open, and it would be just so nice to win it," Federer said, "so I'm going to give myself the best possible chance."

He also knows that his success elsewhere might in a way be a result of his lack of success in the past at Roland Garros, where the year's second Grand Slam tournament begins Sunday. Pretty much everyone expects to see Federer face two-time defending champion Rafael Nadal in the men's final, just like last year.

And just like last year, Federer heads to the French Open hoping to complete a career Grand Slam and a non-calendar Grand Slam.

"I've been working a long time for the French Open goal," he said Friday, "trying to get ready, being in the best physical shape, and, you know, mentally ready."

Turn back the calendar to May 26, 2003, when Federer was an up-and-comer at the French Open. He was 21, seeded fifth, and word was spreading that he was a talented, all-court player who could challenge consistently for major titles.

"I remember going into the tournament feeling so confident," Federer said, "going like, 'I could win this thing. I'm playing so well at the moment."'

What happened? He fell in straight sets in the first round to Luis Horna, a Peruvian ranked 88th at the time.

"I lost the first set and thought, 'There's no chance I'm coming back in this match. And if I do, with seven matches to play, there's no way I'm going to win the French Open.' All of a sudden, within 45 minutes, my whole dreams were shattered," Federer recalled. "I was so weak mentally."

It was a significant turning point.

"I had to toughen up a bit, you know? It was just one of those moments when I finally realized I have to still change a few things," Federer continued. "Because I thought I had everything figured out by then. But I didn't."

He sure seems to now, though.

Since that disappointment in 2003, Federer has won 10 of the past 15 majors — going 93-5 in matches in those Grand Slam tournaments.

If he can win the French Open, it would be his fourth consecutive major championship, something only Don Budge in 1938 and Rod Laver in 1962 and 1969 have accomplished (although they did it within a calendar year). It also would make Federer the sixth man to have won each of tennis' top tournaments at least once. And it would put him on track for a true Grand Slam, given that he's won Wimbledon the past four years and the U.S. Open the past three.