Li, who just nine months ago was celebrating winning the Australian Open title, is one of China's most prolific sports stars and has a huge following, becoming the first player from Asia to win a Grand Slam.

But she has explained how continuing issues with her right knee - which has seen her undergo three operations - has forced her to call it a day.

The 32-year-old told reporters today her decision has left her with no regrets.

"When I made this decision, I asked myself, 'If I retire, will I feel regret?'," she said.

"My heart told me: 'Of course not. I tried my best in my career.' "

Li first burst on to the global tennis radar in 2006 when she made it into the quarter-finals of Wimbledon.

But it was not until the turn of the decade that she really began turning on the style, winning the 2011 French Open and climbing to a career high ranking of number two in the world in February.

She has won nine Women's Tennis Association titles, and come out on top in almost 73 per cent of her 503 career singles matches.

Li Na won the first of her two Grand Slam titles at the 2011 French Open ©AFP/Getty Images



"If you want to keep on a high level, you have to keep the body fit," said Li.

"And now I cannot do that anymore, and so I say maybe now is the time because it's a waste of time if you cannot train 100 per cent but still play.

"This is not myself."

Looking to the future, she added: "What I really want to do now is try to set up a tennis school of my own and do basic things to help build up the base for Chinese tennis.

"Like a pyramid, I believe only with a solid base, Chinese tennis can have a better future."

Li crashed out of the third round of Wimbledon in June - her final competitive match.