A teary-eyed Li Na said on Sunday she has no regrets about her retirement and the Chinese trailblazer was confident her country will produce more grand slam winners in future.

In a letter posted on her Facebook page, the 32-year-old Li, Asia's only grand slam singles champion, announced her retirement on Friday, succumbing to her chronic knee injuries.

The former French Open winner and the reigning Australian Open champion said she had given her best during her career and that was what mattered to her.

"I'm very happy with my whole career and feel very proud. Now is the perfect time to walk away. I don't have any regrets," Li told reporters.

"After I made the decision I asked myself several times, 'will I regret it in the future?' But another voice told me, 'no', and I tried my best on court, so I won't regret it."

Li, known affectionately as 'Big Sister Na' and 'Golden Flower' in China, skipped this year's U.S. Open, triggering speculation her dazzling career was drawing to a close.

For many youngsters in China, she is a role model, with her steely determination, broad smile and English language skills emblematic of a confident and rising country.

Li said tennis in China has undergone vast change since she started and predicted more grand slam champions from her country.

"I've always watched the development of Chinese tennis closely. The young girls now have chances to come into contact with the world's top players face to face, and have a bright future," she said.

"In terms of successors, there's no comparison, everyone has their own features. I believe they'll work hard for their dreams.

"Keep an eye out - they'll be coming. Maybe even better than me," said Li, who wants to do her part by opening tennis school in the future.