Serena Williams saved her best shot at the French Open for last, a crisp whack at a Perrier sign that summed up her frustration.

Whether the crowd took it as an attack on a symbol of France or a show of teenage petulance, the shot sparked derisive whistles that accompanied Williams off center court after a 6-3, 1-6, 6-0 third-round loss today to Mary Joe Fernandez.

Williams was less perturbed by the whistles than all the reckless shots she hit in the match. "Why would I care whether they whistled or not?" she said. "It's my own double fault."

That summed up Williams's day. There were the overheads she clunked long and wide, the volleys she punched 10 feet out, the groundstrokes she hit as if she were trying to drill a hole in the fence. She wound up with 42 unforced errors -- 15 more than Fernandez -- and six double faults. "I couldn't keep the ball in play," she said.

Meanwhile, in men's play, Andre Agassi defeated fellow American Chris Woodruff, 6-4, 6-4, 6-3, to reach the round of 16 and a matchup against defending champion Carlos Moya. Moya, seeded No. 4, beat Sargis Sargsian, 6-3, 7-6 (7-3), 2-6, 6-3.

"To be smack dab in the thick of this tournament feels wonderful," the 13th-seeded Agassi said. "I feel very confident."

Seventh-seeded Tim Henman was upset by Alberto Berasategui, but No. 3 Patrick Rafter and No. 9 Marcelo Rios advanced. In women's third-round play, today's winners included Venus Williams, Martina Hingis, Arantxa Sanchez-Vicario and Jana Novotna.

Serena Williams, 17, had been one of the hottest players on the tour this year, winning titles in Paris and Indian Wells, Calif., and reaching the final of the Lipton, where she lost to her sister, Venus. She came into the French seeded 10th. But on this day, hardly anything worked in a horrendous final set against Fernandez.

"I was out of control," she said. "I had planned on doing very well here, even taking the title. I never even dreamed in my wildest nightmares that I would have went out in the third round.

"There was no excuse for the way I played today, really. I should have been taken off the court immediately and asked to leave the facilities, never to return again."

Williams giggled when she said that, but said she'll take from this match a simple lesson: "Come out prepared and be serious."

Fernandez, the 1993 French Open runner-up, was both. Off the tour much of last year following wrist surgery in 1997, the 27-year-old impressed the top-ranked Hingis when they practiced together in the morning. "She wouldn't miss a ball," Hingis said.

Next up for Fernandez is Sanchez-Vicario, the three-time defending champion who advanced with a 6-4, 6-1 victory over Irina Spirlea.

In other women's third-round matches, Hingis beat Czech Kveta Hrdlickova, 6-3, 6-4; Novotna downed Croatian Silvija Talaja, 6-4, 3-6, 6-4; and Venus Williams beat Australian Alicia Molik, 6-3, 6-1.

In men's play, Agassi came up with the shot of the tournament during his victory over Woodruff. Agassi took a perfect lob to the corner by Woodruff, hit it through his legs with his back to the net and watched it whiz down the line for a winner.

French Open

When: Through June 6.

Where: Roland Garros, Paris.

Defending Champions: Carlos Moya and Arantxa Sanchez-Vicario.

Today's TV: WRC-4, WBAL-11, 12:30 p.m.

Today's Featured Matches: Men -- Gustavo Kuerten (8), Brazil, vs. Sjeng Schalken, Netherlands; Patrick Rafter (3), Australia, vs. Fernando Meligeni, Brazil; Felix Mantilla (14), Spain, vs. Tommy Haas, Germany; Alex Corretja (6), Spain, vs. Gaston Gaudio, Argentina. Women -- Monica Seles (3), Sarasota, Fla., vs. Maria Antonia Sanchez-Lorenzo, Spain; Patty Schnyder (11), Switzerland, vs. Anna Kournikova, Russia; Steffi Graf (6), Germany, vs. Asa Carlsson, Sweden; Julie Halard Decugis (16), France, vs. Cristina Torrens-Valero, Spain; Lindsay Davenport (2), Newport Beach, Calif., vs. Fabiola Zuluaga, Colombia; Silvia Farina, Italy, vs. Jennifer Capriati, Wesley Chapel, Fla.

CAPTION: Andre Agassi beat fellow American Chris Woodruff, 6-4, 6-4, 6-3, and will now play defending champ Carlos Moya. "I feel very confident," Agassi said.

CAPTION: Mary Joe Fernandez is pleased with her 6-3, 1-6, 6-0 third-round victory over Serena Williams, who made 42 unforced errors compared to Fernandez's 27.