Peng Shuai of China hits a return to Tatjana Maria of Germany during their women's singles first round match at the Australian Open 2015 tennis tournament in Melbourne January 19, 2015.  [Photo/Agencies]

MELBOURNE, Australia - With Li Na in retirement and not defending her title at the Australian Open, there are far fewer Chinese flags and fans with red-and-yellow-streaked faces in the stands at Melbourne Park.

So much so that when Peng Shuai, now China's top-ranked tennis player, was beating Magdalena Rybarikova in a second-round match, there was just one fan shouting encouragement in Mandarin with a solitary Chinese flag.

With Li transitioning from tennis star to soon-to-be-mother, her departure from the sport raises an interesting question in China: Can tennis keep its nascent fan base and continue to grow in the country without its global superstar?

"It's literally the billion-dollar question. Ultimately, no one knows" said Richard Heaselgrave, the commercial director for Tennis Australia, which has a considerable stake in the answer as host of the Australian Open, the self-described Grand Slam of Asia-Pacific.

There's no doubting that tennis' popularity has grown immensely in China due to Li's success. According to the WTA, a Chinese television audience of 116 million watched Li become the first Asian player to win a major at the French Open in 2011.

Adding the Australian Open title last year cemented her status as one of China's top celebrities - she now has more than 23 million followers on Sina weibo, China's Twitter equivalent, more than almost all other athletes.

Sensing a golden opportunity, the WTA jumped on Li's success to expand aggressively in Asia, with a record seven tournaments in China this year, second only to the US.

Now that China's biggest star is no longer playing, though, some believe this rapid growth may have been premature.

Zhang Bendou, the tennis writer for Titan Sports, the largest sports newspaper in China, said the crowds were visibly thinner at the Shenzhen Open tournament earlier this month without Li there to defend her title from the year before.

"It's embarrassing to see the pictures," he said. "If the tournaments cannot attract enough sponsors and spectators and media interest, (China) will lose them eventually. I think they are in danger, some of them."

Part of the problem is that because tennis is relatively new to the country, Chinese fans typically only pay attention to the big-name stars and local players, Zhang said.

This partly explains why the men's tennis tour has been more cautious to expand in China _ there are no bankable Chinese men's players yet. Only one made the main draw at the Australian Open - Zhang Ze, who lost in the first round to 33-year-old Australian veteran Lleyton Hewitt.

Heaselgrave is optimistic the Australian Open will retain its Chinese fan base. To help ensure this, Tennis Australia has signed LI to a three-year contract to act as the tournament's unofficial ambassador in China and recently signed a new contract with China Central Television to produce bespoke TV and digital content from the tournament for Chinese consumers.

There's talk of opening Tennis Australia training centers for casual and club-level players in Shanghai and Beijing, as well.

"We're absolutely nowhere near being the Grand Slam of Asia-Pacific that we want to be, but we've made a big start," Heaselgrave said.

The Chinese Tennis Association, meanwhile, is busy trying to find the next homegrown star.

There are now 11 female players ranked in the top 200, led by Peng Shuai, the recent U.S. Open semifinalist, at No. 22. But the one Chinese Fed Cup captain Peng Wang is most excited about is 17-year-old Xu Shilin, the No. 2 girl in the junior rankings, who goes by the English name Coco. The top seed in the girls draw at the Australian Open, she has the potential to be the next Li Na, Peng said.

"Everyone I think in China has confidence now, the coaches, the players," he said. "So they work hard, more than before."