“My previous three surgeries were on my right knee. My most recent knee surgery took place this July and was on my left knee. After a few weeks of post-surgery recovery, I tried to go through all the necessary steps to get back on the court."

Li set a host of milestones for tennis in China, including being the first Chinese player to win a WTA title and the first to win a major.

“I’ve succeeded on the global stage in a sport that a few years ago was in its infancy in China,” she said. “What I’ve accomplished for myself is beyond my wildest dreams. What I accomplished for my country is one of my most proud achievements.

“One of my goals was to recover as fast as I could in order to be ready for the first WTA tournament in my hometown. As hard as I tried to get back to being 100 percent, my body kept telling me that, at 32, I will not be able to compete at the top level ever again. The sport is just too competitive, too good, to not be 100 percent.”

Li won the 2011 French Open, becoming the first player from China to win a grand slam singles title, and clinched the Australian Open title in January in her third trip to the final at Melbourne Park.

She only entered seven tournaments after that, and hasn’t played since a third-round defeat at Wimbledon. She withdrew from three tournaments in August, including the U.S. Open, citing a right knee injury.

She was ranked a career-high second in the world after January's grand slam win, but has slid down to sixth after missing a string of tournaments including the US Open. In July, Li also split with coach Carlos Rodriguez.

The Women’s Tennis Association described Li as a Chinese tennis trailblazer in a statement celebrating her 15-year professional career.

“Li Na has been a fun, powerful, and wonderful player on the WTA tour and, along with her fans, I am sad to hear that she has retired,” WTA chief executive Stacey Allaster said. “In addition to her amazing tennis abilities and her warm and humorous personality, she is a pioneer who opened doors to tennis for hundreds of millions of people throughout China and Asia.

“It’s hard to be a household name in a nation with 1.4 billion people, but that’s what Li Na is.”

The Chinese Tennis Association, in a statement released by the official Xinhua news agency, said it respected her decision and wished her the best.

"We also thank Li Na for the passionate and proud, shining moments she gave to Chinese tennis in her competitive career," it said.

Li first played badminton after being encouraged by her father who played professionally. However, she switched to tennis after being convinced by her childhood coach. She took a break in her career to study journalism only to return to tennis.

Li became a sporting pioneer in China when she decided to break from the state sports system in 2008 with a group of upcoming players, in a move dubbed by local media as "fly alone".

The move meant that Li was able to choose her own coaches and keep most of her winnings rather than give them to the government.

The aggressive baseliner became one of the region's biggest stars when she won the 2011 French Open, becoming the first Asian national to win a grand slam singles title.

She has become a poster girl for the Women's Tennis Association, which has made a concerted push into Asia by organising several new tournaments, including in Wuhan.

Li previously said she considered retiring last year after a dip in form, but following encouragement from Rodriguez, she returned stronger to claim her second grand slam.