Some of the world's top tennis players praised women's world number one Justine Henin following the Belgian's announcement that she is retiring from the sport with immediate effect.

Men's world number one Roger Federer said the news had come as a shock for the tennis world.

"It is particularly surprising that it came one month before the French Open and two before Wimbledon which she has never won," said the Swiss.

"It is surprising and unfortunate that she is out of the game, but she will have had her reasons."

The 25-year-old Henin becomes the first woman in the history of the professional game to retire while ranked Number 1 in the world.

"I thought long about this. I started thinking about it late last year. I was at the end of the road. I leave with my head held high," she said.

"She was a great player and achieved so much, she brought a lot to the women's game," said Ana Ivanovic.

"She had completely different game than any other girl on the tour probably. She worked really hard and last year she had amazing results.

"I'm sorry to hear this thing, but it's her own feeling and her own decision. If she's happy with her career and what she achieved... she won a Grand Slam (seven). She was Number 1 for so long, so she had very successful career."

In Rome, US rival Venus Williams said: "I don't know what the details are, but I think if she made that decision then it's probably the best decision for her.

"Of course my prayers are with her so that way she can continue to lead the life that's best for her.

"She was a great opponent. 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 her best."

Tennis legend Billie Jean King said: "Pound for pound Justine is the greatest player of her generation.

"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."

Henin is the winner of seven Grand Slam titles - also including two US Opens and one Australian Open - 41 career titles and the 2004 Olympic gold.

(DPA - Expatica MAY 2008)