There's no doubting tennis star Li Na's ability, but it's away from the court where her skills are being questioned.

China's first Grand Slam tournament winner has found herself in hot water, not because she failed to make the semi-finals at Wimbledon, but because of her comments.

Li Na of China hits a return to Roberta Vinci of Italy during their women's singles tennis match at the Wimbledon Tennis Championships, in London July 1, 2013. [Photo/Agencies]

With each of her words being interpreted in different ways on the modern professional sports stage, Li faces a hard time in expressing her individuality while maintaining a wholesome public image.

Experts say that Li, who wields considerable influence off the court, should meet this challenge by honing her public relations skills.

"As a professional player, Li should be aware of the fact that her negative emotions after losing matches will be amplified by the media," said Hong Jianping, a sports public relations researcher with the sports and media department of Beijing Sport University.

"By hiring a professional agency to manage her career, Li has become more mature in handling the media than she used to be, but she still needs more advice on how to contain her temper when facing awkward questions."

After losing in the second round of the French Open last month, Li responded aggressively after being asked: "What do you want to say to your home fans in China?"

She replied, "I just lost a match and that's it. Do I need to get on my knees and kowtow to them?"

When the same reporter asked the question again after Li won her third-round match at Wimbledon, the star held back her temper, thanking the fans but criticizing the reporter in a later TV interview.

"How dare he? Doesn't he have any shame?" the 31-year-old said in Chinese.

When the video was put on the Internet, Li's comments drew condemnation in the Chinese media and outrage from postings on China's popular micro-blogging platform Sina Weibo, even among her 21 million followers.

In a commentary carried by Xinhua News Agency, sports journalist Zhang Rongfeng wrote, "Li Na's graceless response has crossed the line from amazing people to hurting people."

A sports consultant said the lack of professionalism in China's sporting system is to blame.

"Professional athletes always keep their tempers under control while showing off their personalities. It's a vocational skill as important as their athletic abilities," said Zhang Qing, founder of sports consulting agency Key-Sports, which provides PR services to athletes and sports organizations.

"Growing up in a system where athletes' media presence was least encouraged, Li's PR ability lags behind her foreign counterparts' even though she's developed in a professional way."

But Li is not the only top player whose PR skills appear in need of some nurturing.

Before crashing out of Wimbledon this year in the fourth round, defending champion Serena Williams triggered debate with comments about a rape victim in Ohio, in a story that appeared in Rolling Stone magazine.

Williams later apologized for what she described as "misinformed comments" in saying the 16-year-old girl "shouldn't have put herself in that position".

The star talked to the victim and the victim's mother, The Associated Press reported. The victim's family forgave her.

British star Andy Murray, who has reached the Wimbledon semi-finals, also ran into trouble with the media during a post-match interview.

Veteran BBC sports journalist Garry Richardson sparked fury from Murray supporters after suggesting the world No 2 should be told off after his remarkable five-set quarterfinal comeback against Fernando Verdasco of Spain.

An indignant Murray retorted: "I don't know it all, far from it. But I don't see why I should get told off for that. I fought as hard as I could, tried incredibly hard, chased every single ball down and I came through an incredibly tough match."

Murray was backed by his fans, but Li, who is also a national hero like Murray, has not been so fortunate.

She may not be able to mend her relations with the media as successfully as Williams has done or enjoy overwhelming support like Murray, but she will learn her lesson in a direct way, according to Lu Hao, president of Starz International, a sports agency representing snooker star Ding Junhui and basketball player Yi Jianlian.

"Li has been the most marketable sports face in China, not only because of her results but also her positive public image. But if such controversy continues to happen, her commercial value will be affected sooner or later," Lu said.

However, Li's agent isn't worried.

Max Eisenbud, IMG senior vice-president who signed Li in 2009, was quoted in a Beijing Youth Daily report as saying, "Li's strong personality helps her attract more endorsement deals, and sponsors have been satisfied with her performance so far."