China's Peng Shuai hits a return on her way to a second-round loss to France's Caroline Garcia at the China Open in Beijing on Oct 5, 2016. Wei Xiaohao/China Daily

"I was near 30 years old (at the time). No one could guarantee I would return to the court after the surgery. And what if I have more injuries afterwards? But I was determined to have the surgery," said Peng.

She continued: "Life is full of challenges and uncertainties. This challenge is quite unique for me. I've worked hard on my tennis for more than two decades. I've sacrificed a lot of my youth, time and energy and I'd like to see how much further I can go in the game."

Peng is certainly no stranger to challenges in her career. After picking up a racket for the first time at the age of 8, she had heart surgery aged 13 to repair a defect.

She returned to the court, however, and turned professional just two years later. In 2005, she became world No 31, which at the time was the highest ranking ever achieved by a Chinese player. She reached her best ranking, No 14, in 2011 and made a major breakthrough in Grand Slams by reaching the semifinals at the US Open in 2014.

Teaming up with Hsieh Su-wei of Chinese Taipei, Peng also won the women's doubles title at Wimbledon in 2013 and the French Open in 2014. They were the world No 1-ranked women's doubles pairing in 2014. Her injury struggles have, though, forced her to consider life after tennis.

"If I retire, maybe I will live a normal life like other people. (Maybe) I will have a family and babies. It's another way of life. But I'm still happy that I made the choice to stay on the court," she said.

"Everything is on the right track now. I don't know whether I can ever again hit the heights I reached earlier in my career but I will try my best."

The match against Williams was Peng's first win in their three matchups and Peng said the fighting spirit of the former world No 1 inspired her to continue on the court.

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