LIMELETTE, Belgium -- The determination that helped Justine Henin beat bigger, stronger opponents time and again was fading.
"I decided," Henin said, "to stop fooling myself and accept it."
Henin retired from tennis Wednesday at age 25, an abrupt ending to a career in which she won seven Grand Slam singles titles and spent more than 100 weeks ranked No. 1.
She announced her decision at a news conference one and a half weeks before the start of the French Open, where she had won the past three titles and four overall.
Put simply, she realized she was burned out, and became the first woman to quit the sport while atop the WTA rankings.
"I always based everything on this motivation -- this flame -- that was in me. And once I lost that, I lost many, many things," Henin said.
Her agent, Ken Meyerson, told ESPN.com's Bonnie D. Ford that Henin called him Sunday evening and, in what he described as a "warm" conversation, said, "I've won everything I need to win, I have more money than I can use in three lifetimes, and I don't have the will to play one day more."
Henin told Meyerson she had been thinking about the decision for five or six months. Her play over that period has been flat, partly because of a troublesome knee that required cortisone treatment, but Meyerson said the reasoning behind her retirement is all emotional.
"She's simply burned out and has no more juice to go on," Meyerson told ESPN.com.
"I was surprised at the urgency of the decision. We, as agents, like long farewells. I'm really sad," he said. "She did so much for the game, and we need her in the women's game. Pound-for-pound, she was one of the best tennis players in history. She was an underdog. She was someone we could relate to."
Surprising as her departure was to the rest of the world, it seemed somehow inevitable to her.
After reaching the final at each Grand Slam tournament in 2006, she won 10 tournaments in 2007, including two majors. But this season, she started to find it an ever bigger chore to pack her luggage to travel to tournaments. Her legs felt heavy when she should have been dancing in the backcourt, ready to turn another one of those sparkling backhands into a winner.
When she was hurt, she no longer minded if an injury lingered. Ever since being discovered as a child prodigy, tennis was everything to Henin. Now, tennis was making it clear that her time was up.
"Everything became harder," Henin said. "I felt, deep inside, something was getting out of my grasp."
At last week's German Open, Henin lost 5-7, 6-3, 6-1 to Dinara Safina. Then she pulled out of this week's Italian Open, citing fatigue.
"At the end of the match in Berlin, [retirement] all of a sudden was there as something evident," Henin said.
Her announcement came a day after one of the greatest female golfers in history said she's quitting: Annika Sorenstam, owner of 10 major titles and one of six women to complete a career Grand Slam in her sport, is walking away at the end of the season.
Henin, however, won't have any sort of farewell tour. She is retiring immediately.
"I had reached my limits, and I feel strong and relieved that I could take this decision," she said. "There are plenty of things that I can do. There are no regrets. I did everything I had to do in tennis."
In an interview with the French sports newspaper L'Equipe on Wednesday, Henin was asked if she could change her mind.
"It's a final decision even though some people will think the opposite," she said, according to the paper. "I know it's a shock for a lot of people, but I'm leaving without regrets, feeling relieved. It took some courage because I know there will be things I miss."
In addition to her four French Open titles, Henin won the Australian Open in 2004, and the U.S. Open in 2003 and 2007. She has been ranked No. 1 since Nov. 13, 2006, except for a seven-week period last year when Sharapova held the top spot, and won nearly $20 million in career prize money.
"She was a great champion," said Williams, who lost to Henin in a contentious 2003 French Open quarterfinal, "and she gave me a world of trouble."
The only Grand Slam title to elude Henin is Wimbledon, where she was runner-up in 2001 and 2006.
"Winning Wimbledon would not make me happier than I am," she said.
Winning again at Roland Garros would make no difference, either, no matter how much that event means to her. Henin dedicated her first victory there to her mother, who died of cancer when Justine was 12. When Henin won there last year, it capped a reunion with her father and siblings, from whom she'd been estranged for several years.
"That was awesome. It was a great feeling, and I am going to keep that feeling forever now," she said. "I won Roland Garros four times, three times in a row. I don't have to live that moment again. I know how it was."
Throughout her career, Henin has had to beat the odds.
With her 5-foot-5¾, 126-pound frame, she had to figure out how to deal with foes who could hit the ball harder. With a superb one-handed backhand, amazing speed and grit, she rose to the top of the sport.
"She always challenged herself to play her best tennis no matter what the circumstances. She was just a real fighter, so I think that was really what made her best," Venus Williams said.
"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."
L'Equipe asked Henin how she would want to be remembered.
"That I was a different player -- the little one who came and challenged the bigger ones," she said.
Henin was away from the tour for months at a time in 2004 and 2005 because of an energy-sapping blood virus and assorted injuries, including to her knee and back. In early 2007, she divorced from Pierre-Yves Hardenne and dropped his last name.
Throughout last season, Henin said she had finally found a balance in her life between personal self-fulfillment and doggedly pursuing tennis titles.
Now it appears that changed. Perhaps she took note when Kim Clijsters -- another Belgian who was ranked No. 1 and won a Grand Slam title -- retired at 23 last year. Clijsters has since married and become a mother.
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."
The news conference was at the Justine N1 academy in a village about 20 miles outside of Brussels. It has a smattering of her beloved clay courts, where she wants to train and coach youngsters.
"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," Henin said. "I take this decision without the least bit of regrets. It is my life as a woman that starts now."
Bonnie D. Ford, who covers tennis and Olympic sports for ESPN.com, and The Associated Press contributed to this report.