The Associated Press

PARIS - Serena Williams has entered a new realm coming into the French Open. She has won four straight majors, a self-styled "Serena Slam." She claimed the No. 1 ranking from her older sister. She sparked talk of an undefeated season and had some wondering whether she might need to pull a Sorenstam and play against men to find a true challenge.

And that's just on the court. Away from it, too, Williams fully emerged from Venus' shadow, dabbling in acting and modeling, finding her adult voice.

This is not to say everything in the past 12 months went as she would have wanted. Her parents divorced; a stalker was arrested at Wimbledon and the U.S. Open.

She seems to be handling it all as well as anyone could at 21.

"I'm more mature. I've experienced a lot more in life, on and off the court," Williams said.

When play starts at the French Open on Monday, Williams will have a chance to win a fifth straight major title, something last accomplished by Steffi Graf in 1988-89.

Suddenly, however, other players might truly believe that another all-Williams Grand Slam final isn't such a sure thing. After opening 2003 with 21 straight victories, Serena lost twice - gasp! - in about a month: against Justine Henin-Hardenne in Charleston, S.C., and against Amelie Mauresmo in Rome.

"She can be frustrated," Henin-Hardenne said.

And Venus Williams has fallen to No. 3 in the rankings.

"Everybody's playing better these days," Serena said. "We've definitely raised the bar."

Both statements are true. The challengers include Mauresmo, a semifinalist at Wimbledon and the U.S. Open last year; Henin-Hardenne, the 2001 French Open runner-up; Kim Clijsters, who supplanted Venus at No. 2 and has won the same number of tournaments this year as Serena (three); and 2001 champion Jennifer Capriati.

The men's tournament is wide open. Plenty of players could make a strong case that they'll win, from top-ranked Lleyton Hewitt, to eight-time Grand Slam champion Andre Agassi, to 2002 finalist Juan Carlos Ferrero, to 1998 champ Carlos Moya, to three-time winner Gustavo Kuerten, to fifth-seeded Roger Federer.

As Agassi's coach, Darren Cahill, put it: "Andre is one of the favorites, along with guys like Hewitt, Ferrero, Moya and Federer. Unlike the other Grand Slams, the French Open presents an opportunity for a lot of people to win."

French Open at a glance

When: Monday-June 8.

Top seeds: Men, Lleyton Hewitt; Women, Serena Williams.

Defending champs: Men, Albert Costa; Women, Serena Williams.

On TV: Monday, 8 a.m., ESPN2