Nadal fires Olympic warning

The Australian, former number one, had played a grueling doubles match that stretched into the early hours of Tuesday after going to 18-16 in the third set, and his tiredness showed, notably on his backhand returns.

Hewitt, currently ranked 38 in the world, managed to break Nadal in the first game of the second set in a short-lived revival but the Spaniard stole the march again and soon had the match wrapped up.

Also in blistering form on Tuesday were the Williams sisters and the Serbian duo of Jelena Jankovic and Novak Djokovic.

Jankovic, the women8217;s world number one and Olympics top seed in the absence through injury of Ana Ivanovic, beat Ukraine8217;s Alona Bondarenko 7-5, 6-1.

The Serbian broke Bondarenko three times in the second set and put the match away with a lightning backhand pass down the line.

The 23-year-old from Belgrade was wearing a strapping on her troublesome right calf and did not look completely at ease but said she hoped it would continue to get better.

8220;I took some painkillers to be able to play, otherwise it8217;s quite sore,8221; Jankovic said.

8220;It was already much better than yesterday when I was in a lot of pain. But today it was better and I hope to be improving further for Wedensday.8221;

Jankovic8217;s compatriot Djokovic, seeded third in the men8217;s draw, progressed confidently against Germany8217;s Rainer Schuettler 6-4, 6-2.

But Russian fourth seed Nikolay Davydenko crashed out 7-5, 6-3 to Paul-Henri Mathieu.

Mathieu will join French compatriots Gilles Simon, the 10th seed, and Gael Monfils in the third round after their respective wins over Guillermo Canas of Argentina and Romanian Victor Hanescu.

There was also a win for 17th-seeded Czech Tomas Berdych over Italy8217;s Andreas Seppi, and a win for Belgian Olivier Rochus who was a set ahead of Janko Tipsarevic when the Serbian retired injured.

The Williams sisters both earlier confirmed their status as among the hot favourites for gold in the women8217;s singles, which has been hit by a raft of withdrawals.

Fourth seed Serena took just 44 minutes to dispatch Australia8217;s Samantha Stosur, the American eight-time Grand Slam champion breaking at 3-2 and taking complete control to reel off the last 10 games to love.

8220;It was clean,8221; said Williams, who missed the 2004 Games in Athens through injury. 8220;My way of improving on it is to keep it up.8221;

The 2000 doubles winner8217;s round-three opponent is French 15th seed Alize Cornet, who subdued a vociferous home crowd in outclassing China8217;s Peng Shuai 6-2, 6-2.

Serena8217;s sister Venus, the seventh seed, demolished Iveta Benesova of the Czech Republic, 6-1, 6-4.

8220;I definitely feel more confident with every match that passes. That8217;s what winning does,8221; she said.

Russian sixth and ninth seeds Dinara Safina and Vera Zvonareva also stayed in the mix with wins over Spaniard Maria Jose Martinez Sanchez and Israeli Shahar Peer, while Slovakian 16th seed Dominika Cibulkova cruised past Bulgaria8217;s Tsvetana Pironkova.

But two other women8217;s seeds were knocked out in morning play.

Daniela Hantuchova of Slovakia, the 10th seed, was thrashed by Danish teen Caroline Wozniacki, and Polish eighth seed Agnieszka Radwanska went down to Italian Francesca Schiavone.