PARIS -- After she had beaten Serena Williams to reach the semifinals at the French Open, an ecstatic Jennifer Capriati had a long list of thank-yous.
She thanked her new coach, Heinz Gunthardt, her father Stefano, fitness trainer T.R. Goodman, massage therapist Theresa Ferguson, and the WTA trainers. She didn't mention the one thing -- well, two, actually -- that has made her the overwhelming favorite to win her second championship at Roland Garros: her feet.
While everyone likes to focus on the big serves, heavy ground strokes and unforced errors, Capriati's success on clay has more to do with her footwork than you might suspect. At 5-foot-7, 160 pounds, Capriati is not exactly delicate -- but her small, nuanced ballet-like steps would be right at home in a Degas painting in the nearby Louvre.
"In the beginning of the year, when she was a little out of shape, she was a little slower than usual and it affected her shot-making," explained ESPN analyst Mary Joe Fernandez, a finalist here in 1993. "She would hit the ball and wait. Now, she's fit and when she hits it, she's already reacting to the next shot. Her initial push off, her small steps, put her in great position. Even though she's a bigger player, her movement is really quite precise."
Footwork on clay is, understandably, a more difficult proposition than it is on hard courts. Instead of being able to plant your feet with confidence, clay is a loose, shifting, fluid surface. Playing on clay tests balance and coordination, something like running on a sandy beach. Because clay is more forgiving, the ball hangs in the air longer, prolonging points, games and matches. Footwork becomes even more important.
Watching the best players rally, it's easy to forget about their feet. Their artistry can be breathtaking, but the shot itself is only the final stroke in a series of complex actions. Getting to where the ball is going to be -- before it gets there -- requires intuition and the ability to place yourself precisely where you need to be to hit the ball with maximum power and efficiency. The ability to slide comfortably is mandatory.
Balance -- in life and tennis, as well -- is a critical element. Unlike Serena and Venus Williams, who often seem to be swinging awkwardly at balls that are too close to them, Capriati is as smooth as a seal running with the waves.
This is not a coincidence.
Capriati was 4 years old when she started training at Jimmy Evert's tennis center in Fort Lauderdale, Fla. There are 18 Har-Tru green clay courts there.
"She grew up on green clay, as I did," Fernandez said. "We had a lot of junior tournaments on clay and the Orange Bowl used to be played on clay. It becomes second nature."
Of all the Grand Slams, Fernandez felt most comfortable here at Roland Garros. She reached five quarterfinals here and, memorably, in 1993 rallied to beat Gabriela Sabatini and ultimately lost to Steffi Graf after taking the first set in the final. In 1990, Fernandez lost to a 14-year-old Floridian in the quarters, who went on to become the youngest French Open semifinalist ever. Her name was Jennifer Capriati.
Most observers didn't give Capriati much of a chance against Serena Williams in Tuesday's quarterfinal match. She had beaten her 17 days earlier in Rome, but it was only Williams' 14th match of the year after eight months away from the game following knee surgery.
But Roland Garros revealed faulty footwork by Serena and her long-legged sister Venus.
"Both of them are very good on the run," Fernandez said. "They can go out wide a long distance very quickly. That's where their great angles come into play. Where they get into trouble is when it's close to them. You see people play them up the middle because it's tougher for them to take those little steps.
"On a hard court they can plant better and be more stable. But, more than anything, that last-second adjustment can be tough for them. Watch Justine Henin-Hardenne, she just sort of flows along the ground. Tracy Austin was the queen of little steps and that last, split-second movement. The Williams sisters, with their big gliding kind of steps, cover a lot of ground, but it's not such an advantage."
This, Capriati seems to understand.
Her goal was to keep Serena moving, early and often.
"The longer the points went, I felt like that was to my advantage," Capriati said after the match. "I wanted to move her around, not give her a rhythm, but not open up the court too much because she likes hitting those angles.
"When in doubt, you just try to hit hard up the middle because even for any player it's difficult. Even on the serve, you know, you just try to hit more into the body."
Venus Williams' undoing in her quarterfinal with Anastasia Myskina was a balky left ankle, which she sprained in the semifinals of Berlin two weeks before the French Open. Her footwork was, thus, challenged from the beginning. The Williamses combined for 88 unforced errors and are already back at home in Palm Beach Gardens, Fla., contemplating Wimbledon.
Meanwhile, Capriati is focusing on the fourth Grand Slam singles title of her career. At 28, this is an unlooked for opportunity. She is the No. 7 seed here, but with the absence of last year's two Belgian finalists, Henin-Hardenne and Kim Clijsters, the Williams sisters and No. 3-seeded Amelie Mauresmo -- surprising loser to Elena Dementieva -- Capriati is the only semifinalist who has even been to a Grand Slam final.
Capriati meets Myskina in one semifinal, while Paola Suarez plays Elena Dementieva in the other. The two Russians are quite comfortable on clay, and Suarez ranks her finest memory in tennis playing for the 1992 junior title here at Roland Garros.
After her victory over Serena Williams, Capriati talked about ending a numbing streak of eight straight three-set losses.
"You have to take it like a fighter, you know," Capriati said. "You're going to get punched and you've got to take the blows and just keep coming back.
"And you know, that's why it just feels like a huge weight lifted off my shoulders. But I'm not going to like be too happy about it. I've got another match."
And if Capriati survives for one more match after that and holds the classic sterling cup aloft, she will have her feet to thank.
Greg Garber is a senior writer for ESPN.com.