The world's best tennis players secured respective opponents in the upcoming Beijing Olympics as the draw was revealed on Thursday.

Current world number ones Roger Federer and Ana Ivanovic will play Russian 35th-ranked Dmitry Tursunov and Mariya Koryttseva of Ukraine, while second seeds Rafael Nadal and Jelena Jankovic, both soon to become the new world number ones, will play Italian Potito Starace and Cara Black of Zimbabwe.

Federer, going through the worse season since he became the world number one in 2004, will find many of his nemeses in his quarter featuring Frenchman Gilles Simon and Croat Ivo Karlovic, both winning over the Swiss in ATP Masters events held in North America last month.

If all goes well, the big-serving Karlovic will meet Federer in the third round, a rematch of the Cincinnati Masters weeks ago when the Croat claimed the first career win over Federer after a six-match losing streak. But he has to first defeat Czech Tomas Berdych in the opening round and the winner of Spaniard Tommy Robredo and Andreas Seppi from Italy in the second.

The top half of men's singles draw also features Russia's fourth seed Nikolay Davydenko, who will face 38-ranked Ernests Gulbis from Latvia. The Russian master heads towards a would-be quarterfinal clash agaisnt Spanish fifth seed David Ferrer, who will take on a hard first round match against Serb Janko Tipsarevic.

After claiming his fourth consecutive French Open trophy, Nadal beat Federer again at Wimbledon in a five-set epic on the Swiss maestro's Centre Court fortress. What's more, the bull-like youngster seems to improve on hard court too, winning the Masters event in Toronto and reaching the semifinals in Cincinnati last month.

"I came here to represent my country and I will do my best to claim a medal for Spain," said Nadal in a press conference on Wednesday night, having played the men's doubles event with Carlos Moya in Athens four years ago.

He might in the second round face Australian Lleyton Hewitt, who kept a 4-3 record in career and if all goes to plan, the upsurging Scot Andy Murray, who has just claimed the first career Masters title in Cincinnati, will be waiting for him in the quarterfinals.

Murray, rising to a career best sixth on the world rankings, will not fire on all cylinders playing Chinese Taipei's Lu Yen-Hsun in the opening round.

The bottom half will also include challengers like Serb's world number three and Australian Open winner Novak Djokovic, ninth seed Stanislas Wawrinka, another Swiss Olympic medal hope, Argentine seventh seed David Nalbandian and Spanish talent Nicolas Almagro.

In women's part, fourth seed Serena Williams, Russian fifth seed Elena Dementieva and ninth seed Vera Zvonareva will compose the main challenge towards the French Open winner Ivanovic.

This year, the Serbian sensation will compete in her first Olympic Games and her country's eyes will all be on her. Ranked No. 1 in the world for nine weeks during a memorable 2008 so far -- winning her first Grand Slam title at Roland Garros and finishing runner-up at the Australian Open, among other achievements -- adding an Olympic medal would round off a great year for her.

But the 20-year-old, who has been nursing her injury in her right thumb, might be facing a strong task in a possible second round meeting against Frenchwoman Tatiana Golovin, and if she can make it through to the next round, Ivanovic will have to apply more work as a tough-minded Patty Schnyder could stand in the way.

American Serena Williams was handed an easy draw and she will not face strong challenge until a potential quarterfinal meeting against Dementieva.

Jankovic, who will replace Ivanovic on the top spot next week, is in a much harder position than her compatriot Ivanovic as third seed Svetlana, sixth seed Dinara Safina, America's seventh seed and Wimbledon winner Venus Williams and Hungary's Agnes Szavay are all posing serious threat.

After winning back-to-back titles in Los Angeles and Montreal, Safina has become one of the heaviest favorites for the Olympic title. She will take on Nara Santangelo from Italy in the opening match.

The Chinese women players, who have improved in recent years, were given a tough draw on their home soil, as Wimbledon semifinalist Zheng Jie faces eleventh seed Szavay while Li Na, the former top 20 player, will take on Kuznetsova in the opening round.

Zheng's long-time partner Yan Zi needs to do her best facing Russian Zvonareva and Peng Shuai takes on Spain's Carla Suarez Navarro.

Countries are allowed a maximum of six players in the Olympic tournament with no more than four in the singles. They are allowed two doubles pairs.

Tennis was a part of the first modern Olympic Games in 1896 but was withdrawn after the 1924 Paris Games. It returned as a demonstration event in the 1984 Los Angeles Games and became a full medal sport again in 1988.

The Beijing tennis tournament will be held between August 10-17.

(Xinhua News Agency August 7, 2008)