The tennis world has been paying tribute to Justine Henin, who announced her immediate retirement on Wednesday.

ROGER FEDERER (Switzerland), men's world number one: "It's obviously a shock for the tennis world. It's a particular surprise before Roland Garros and Wimbledon, which she's never won.

"It's quite surprising and unfortunate that she's out of the game but she will have her reasons.

"She is a special player because she can play on any surface and it's remarkable that she's won so many tournaments because she is small and the tall players coming in now have an advantage.

"I couldn't imagine deciding out of the blue to retire, especially if I was number one. I would prefer to take a year off if it was all getting too much for me, rather than saying straight out that I'm not going to go on."

MARIA SHARAPOVA (Russia), women's world number two behind Henin: "She's 25 years old and she's achieved so much in her career. If I was 25 and I'd won so many grand slams I'd quit too.

"Without being the strongest or the biggest, she's won so much. She's an inspiration. There's so many things to life and I'm sure she wants to explore them. I definitely don't blame her for retiring."

VENUS WILLIAMS (U.S.): "She was a great opponent. She always challenged herself to play her best tennis, no matter what the circumstances. A real fighter."

SERENA WILLIAMS (U.S.): "She was a great champion and she gave me a world of trouble, so I hope the best for her. What can you say about such a great champion? I don't think we have enough time."

JELENA JANKOVIC (Serbia): "I was very surprised by her retirement because she's doing very well and she's still young. She's great for the game.

"It can sometimes be very difficult, many years playing and travelling around the world. Being there, being at the top, can be very difficult. We will miss her."

ANA IVANOVIC (Serbia): "(Tennis loses) another champion, a great player who brought a lot to the women's game. She had a different game to any other woman on the tour. I'm sorry to hear this."

BILLIE JEAN KING (U.S): "Pound for pound Justine is the best 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, a special person and a true champion in both tennis and in life."

CARLOS RODRIGUEZ (Henin's coach): "Technically and tactically she has it all. But I think she will be remembered for the way in which she won and lost and the way she never gave up no matter what was going on in her life.

"She never craved fame and money. All she wanted to do was play and win."

LARRY SCOTT (WTA Tour chief executive): "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.

"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.

"History will remember Justine for not only her seven grand slam titles and three years finishing as the WTA Tour's world number one 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 the tennis court and off."

FRANCESCO RICCI BITTI (ITF president): "Justine Henin has been an outstanding athlete of her generation, and had a grace and style on court that distinguished her from other players. She has always been one of my favourite players to watch.

"Her victory at the 2004 Athens Olympics was Belgium's only gold medal at the Games and we are sorry that she won't be able to defend her title in Beijing. She has made a huge contribution to the sport."

Reuters