Limelette, Belgium -- (Sports Network) - Top-ranked Belgian star Justine Henin has decided to retire from professional tennis, effective immediately, as she becomes the first-ever reigning women's world No. 1 to call it quits.

Henin held a Wednesday afternoon news conference to announce her decision. She is the second Belgian stalwart to retire over the last two seasons, as her former rival Kim Clijsters quit the WTA Tour last year in order to start a family.

"The decision is final, I stop immediately with tennis," said Henin, who was flanked by her long-time coach Carlos Rodriguez. "I stop without regret. I've given everything."

Henin added that she is "not sad, but relieved and proud."

The 25-year-old Henin, who will turn 26 on June 1, went 16-4 this year, including a third-round exit in Berlin last week. She withdrew from this week's Italian Open, citing fatigue, something that forced her out of several events over the past several years.

A four-time French Open champion, Henin captured seven Grand Slam titles among her 41 overall career titles. She first rose to No. 1 on October 20, 2003, and this week marked her 61st consecutive one at the top of the rankings and 117th overall, which is good enough for sixth on the all-time list.

The winner of the last three championships at Roland Garros, Henin had two titles this year -- in Sydney and Antwerp. She was ousted by Russian superstar Maria Sharapova in the quarterfinals at the Australian Open, the first Grand Slam event of 2008.

The 5-foot-5 Henin, best known for her spectacular backhand, tremendous athleticism and unrivalled work ethic, led the tour with 10 titles last year, including ones at the French and U.S. Opens, and pocketed over $5 million in prize money. Her career prize money eclipsed $19 million.

Her stunning announcement comes less than two weeks before the start of the 2008 French Open, where she'd won her last 21 matches.

"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," said WTA Tour chairman and CEO Larry Scott. "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. History will remember Justine for not only her seven Grand Slam titles and three years finishing as the Sony Ericsson WTA Tour's No.1, but for one of the most graceful backhands the sport has ever seen and an ability to overcome any and all obstacles placed in her way on and off the court."

"This is a sad day for our sport and for her millions of fans around the world, but I know that I speak for so many in wishing Justine the very best in her future endeavors and hope that she will stay connected to the sport to which she gave so much," Scott added.

Henin captured every major tennis event, with the exception of Wimbledon. She even helped tiny Belgium win its first and only Fed Cup title back in 2001 and was a two-time winner of the prestigious year-end Tour Championships.

"Pound for pound Justine is the greatest player of her generation," said WTA Tour founder and tennis legend Billie Jean King. "I trust she has not come to this decision quickly or easily and I wish her the very best. Justine is an extraordinary player and a special person and a true champion both in tennis and in life."

The 2004 Olympic gold medalist Henin has always been plagued by a troubled personal life, as her mother died in 1995, she did not speak to her father for eight years, and divorced her husband, Pierre-Yves Hardenne, in 2007.