Led by the two world No.1s, Beijing Olympics bronze medalist Novak Djokovic of Serbia and Russia's Maria Sharapova, 19 of the current world's top 20 will contest both the men's and women's events, with the exceptions being American Mardy Fish and Frenchwoman Marion Bartoli.

But that will not be a problem for Sun Jinfang, head of the Chinese tennis governing body, who has overseen a series of breakthroughs in the last two Olympics.

"You never know what could happen in the Olympics," she said. "It's not like a regular tournament. We have four Grand Slams every year but the Olympics comes around once every four years so there's more pressure and there are eventualities.

"Of course it's very challenging given the singles entry, but I hope the players can bring us more surprises and make the country proud."Four Chinese players have qualified for the Olympic tennis event, which runs from July 28 to August 5. Li, last year's French Open winner, will be joined by Zheng Jie and Peng Shuai in the women's singles draw. Peng and Zheng will also team up for the doubles, while Li will compete alongside Zhang Shuai.

It's a reduced participation compared to that of last Olympics in Beijing, but the players are much-improved.

The 30-year-old Li rocketed to fame when she captured the 2011 French Open title to become Asia's first Grand Slam singles champion.

Although Li has failed to win another trophy since the Paris breakthrough, the world No. 11 still proves to be a medal contender at Olympics.

"I am looking forward to playing at the Olympics. This could be my last time to play for my country at the Olympics as I'm already 30 years old and you never know what will happen after four years," Li said during this year's Wimbledon.

The grasscourt Grand Slam event, which ended at the All England Club on Sunday, will be followed by the Games just three weeks later as Olympic tennis returns for the first time since 1908.

In 1908 when London held its first Olympics, Wimbledon was the venue of the tennis tournament. When London played host to the 1948 Games, tennis had been ruled out of the quadrennial extravaganza.

Li said she can't wait to get back to the All England Club for the Games.

The usual clothing restrictions will be relaxed at the traditionalist All England Club for the Olympic tennis tournament, with players wearing the national colors instead of the regulation white.

"I'm also looking forward to seeing Wimbledon without people wearing white," she said.

"In the Olympics you can wear the country's color to play in Wimbledon so I'm looking forward to seeing that. In more than 100 years nothing has changed here so maybe it's the only time in a lifetime you can see this with colors."At Wimbledon, Li had some sweet memories. She had twice been a quarterfinalist at the All England Club -- losing to Kim Clijsters in 2006 and to Serena Williams at the same last-eight stage in 2010.

Despite Li's headline-grabbing Grand Slam performances, China's best singles run at Wimbledon was Zheng's semifinal surge in 2008 which was ended by Serena Williams of the United States.

The Sichuan right-hander came so close to exacting a revenge at this year's Wimbledon where she gave Williams, the eventual winner, a real scare in the fourth round.

If Zheng maintains her form, Sun claimed, she will be a dangerous prospect in the Olympic draw.

Zheng and her former partner Yan Zi were also crowned as doubles champions here in 2006, and in this year's London Games, she will pair up with Peng, a new team that is little known to their opponents.

"We only played together on a couple of occasions this season because both of us have different tournaments to contest. Maybe Peng and I did not get a lot of practice and matches together like I did with Yan, but it's becoming an advantage for us, because our opponents will know little about our tactics," Zheng said.

The 28-year-old was so eager to do well in the Olympics that she even participated in the mixed doubles event at Wimbledon. "I just want to get more feeling about doubles and grass."Zheng and Yan won the bronze medal in the Beijing Olympics four years ago, this time she wants a better result.

The Williams sisters will be the major opponents for the Chinese women in the grasscourt Olympic event, and they'll play singles as well as doubles.

Serena Williams on Saturday has just won the Wimbledon for the fifth time and also teamed up with her sister Venus to grab their fifth doubles' title on the same day.

The pair never lost in Olympic doubles competition while taking the gold together in 2000 and 2008.

Venus Williams also won the gold in singles in 2000, and she's the only three-time gold medalist in U.S. tennis history. When the London Games begins, she'll become the first American tennis player to compete in four Olympics.

Other major contenders in women's singles include Australian Open champion Victoria Azarenka of Belarus, Russia's French Open winner Maria Sharapova, U.S. Open winner Samantha Stosur from Australia and Czech Petra Kvitova, winner of last year's Wimbledon.

This year's Wimbledon runner-up Agnieszka Radwanska of Poland and former world number one Caroline Wozniacki of Denmark are also among the medal hopefuls.

In the women's doubles, besides Williams sisters, Andrea Hlavackova/Lucie Hradecka (Czech Republic), Sara Errani/Roberta Vinci(Italy), Agnieszka Radwanska/Urszula Radwanska (Poland), Maria Kirilenko/Nadia Petrova (Russia), Nuria Llagostera Vives/Maria Jose Martinez Sanchez (Spain) and Liezel Huber/Lisa Raymond(United States) all have chances of taking medals.