Beijing - Rafael Nadal continued his march towards Beijing Olympic honours with a 6-1, 6-2, thrashing of former number one Lleyton Hewitt on Tuesday.

The Spaniard, who takes over the top ranking on Monday from Roger Federer, was ruthless as he handed the Australian a comprehensive defeat to reach the third round.

Nadal was joined as a winner by third seed Novak Djokovic, a 6-4, 6-2 victor against German Rainer Schuettler, who was controversially admitted to the Games by the Court of Arbitration for Sport.

Austrian Jurgen Melzer shocked number 10 Stan Wawrinka of Switzerland, 6-4, 6-0, while Lu Yen-Hsun of Taiwan, who eliminated Andy Murray in the first round, continued to make progress by beating Agustin Calleri 6-4, 6-4.

The Williams sisters crushed the opposition with ease in the women's draw.

Wimbledon winner Venus hammered Czech Iveta Benesova 6-4, 6-4 and sibling Sernea was untroubled by Australian Samantha Stosur, 6-2, 6-0 in a 44-minute exercise.

Serena Williams, eight times a Grand Slam winner, won the final ten games without a point produced from the Stosur side.

"My way of improving on it is to keep it up. I'm playing consistently, it was a clean win," said Williams, who played in Sydney but missed the Athens Games through injury.

Other winners included sixth-seeded Dinara Safina and rising stars Alize Cornet and Caroline Wozniacki, the latter upsetting 10th seed Daniela Hantuchova 6-1, 6-3.

New WTA number one Jelena Jankovic of Serbia began her reign with a victory against Ukraine's Alona Bondarenko 7-5, 6-1.