LIMELETTE, Belgium — Justine Henin retired from tennis today, an abrupt ending to a short and successful career in which she won seven Grand Slam singles titles and leaves while ranked No. 1.

The 25-year-old Belgian made the surprising announcement at a news conference, less than two weeks before the start of the French Open. She has won that clay-court major championship four times, including each of the past three years.

“This is the end of a child’s dream,” said Henin, the first woman to retire from tennis while atop the WTA rankings. “This is a definitive decision. Those who know me know it is serious.”

Her announcement came a day after one of the greatest female golfers in history said she’s walking away: Annika Sorenstam, owner of 10 major titles and one of six women to complete a career Grand Slam in her sport, is retiring at the end of the season.

Henin, though, won’t have any sort of farewell tour. She is quitting immediately.

“It is a new beginning for me. I feel like I already lived three lives. I gave the sport all I could and took everything it could give me,” she said. “I take this decision without the least bit of regrets. It is my life as a woman that starts now.”

Henin won 10 tournaments last year, but has been in one of the worst slumps of her career this season. She lost last week in the third round of the German Open and pulled out of this week’s Italian Open, citing fatigue.

“I thought long about this,” Henin said, her voice cracking and eyes watering. “I started thinking about it late last year. I was at the end of the road. I leave with my head held high.”

Last year, Kim Clijsters — another Belgian who reached No. 1 and won a Grand Slam title — retired from tennis at 23. She has since married and become a mother.

The 5-foot-5 3/4, 126-pound Henin overcame her slender build and a litany of injuries to dominate tennis for long stretches, thanks to a superb one-handed backhand, impressive court coverage and grit.

“She was a great opponent. She always challenged herself to play her best tennis no matter what the circumstances,” Venus Williams, a six-time major champion, said Wednesday at the Italian Open. “She was just a real fighter, so I think that was really what made her best.”

Henin was 12 when her mother died of cancer, and became estranged from her father and siblings for nearly a decade before reconciling last year.

In 2006, she reached the finals of every Grand Slam tournament. In 2007, she sat out the Australian Open in January while going through a divorce from Pierre-Yves Hardenne, then returned to the tour and won the French Open and U.S. Open, eight other tournaments and more than $5 million.

However, after winning her home tournament in Antwerp in February, she has failed to go beyond the quarterfinals at any other event this season.

Henin’s year began with a 6-4, 6-0 loss to Maria Sharapova in the Australian Open quarterfinals in January, followed by a 6-2, 6-0 drubbing by Serena Williams at the Sony Ericsson Open in April, the worst loss for a top-ranked player in nine years.

At last week’s German Open, Henin lost 5-7, 6-3, 6-1 to Dinara Safina.

“At the end of the match in Berlin, (retirement) all of a sudden was there as something evident,” Henin said. “I decided to stop fooling myself and accept it.”

Dressed in a simple white T-shirt and jeans, her brown hair in a ponytail, Henin spoke in French for nine minutes before taking questions Wednesday. She never lost her composure and held the microphone firmly.

But her coach, Carlos Rodriguez, broke down in tears.

“Because of her,” Rodriguez said, “I am somebody.”

In addition to her French Open titles, Henin won the Australian Open in 2004, and the U.S. Open in 2003 and 2007. The only Grand Slam title to elude her was Wimbledon, where she was the runner-up in 2001 and 2006.

“Winning Wimbledon would not make me happier than I am,” she said. “I could never dream of Wimbledon. It was destiny. I didn’t feel myself capable. It was too much for me.”

Henin, who earned nearly $20 million in career prize money, has been ranked No. 1 since Nov. 13, 2006, except for a seven-week period last year when Sharapova held the top spot.

“Justine Henin will be remembered as one of the all-time great champions in women’s tennis, and a woman who made up for her lack of size with a will to win and fighting spirit that was second to none,” WTA Tour CEO Larry Scott said. “It is rare that an athlete leaves at the very top of her game in this day and age, but Justine has always played by her own rules, in the very best sense of those words.”