BEIJING, August 12, 2008 (AFP) - The top three seeds in the Olympics men's singles, Roger Federer, Rafael Nadal and Novak Djokovic, all moved easily into the third round with convincing wins here on Tuesday.

The women's draw also saw dominant performances from the Williams sisters and Serbian world number one Jelena Jankovic.

Swiss top seed Federer breezed to a 6-2, 6-4 win over inexperienced but game Rafael Arevalo of El Salvador, ranked 447th in the world and only playing in the Games because of his country's small number of competitors.

Nadal crushed Lleyton Hewitt 6-1, 6-2, while Serbian third seed Djokovic beat German veteran Rainer Schuettler 6-4, 6-2.

Nadal, who will take over from Federer as world number one next week, was always in full control against the Australian former number one now ranked 38.

Hewitt had played a gruelling doubles match that stretched into the early hours of Tuesday after going to 18-16 in the third set and his tiredness was noticeable as he crumbled under Nadal's relentless attack.

'I played very well. It was one of the best matches I have played,' said Nadal.

The Spaniard will play Russian Igor Andreev in the third round, with Federer meeting Czech Tomas Berdych, the 17th seed, and Djokovic facing a tricky tie against Russian 13th-seed Mikhail Youzhny.

Defending Olympic champion Nicolas Massu of Chile was dumped out by number seven seed David Nalbandian, while Russian fourth seed Nikolay Davydenko went down 7-5, 6-3 to Paul-Henri Mathieu.

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

In the women's draw, the Williams sisters and Jankovic were in blistering form.

Jankovic, the top seed in the absence through injury of Ana Ivanovic, brushed aside Ukraine'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.

'I took some painkillers to be able to play, otherwise it's quite sore,' Jankovic said.

'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 Wednesday.'

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

Fourth seed Serena took just 44 minutes to dispatch Australia'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.

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

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

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

'I definitely feel more confident with every match that passes. That's what winning does,' she said.

Russian fifth, sixth and ninth seeds, Elena Dementieva, Dinara Safina and Vera Zvonareva, also stayed in the mix while Slovakian 16th seed Dominika Cibulkova cruised past Bulgaria's Tsvetana Pironkova.

But three other women's seeds were knocked out.

Slovakia's Daniela Hantuchova, the 10th seed, was thrashed by Danish teen Caroline Wozniacki, Polish eighth seed Agnieszka Radwanska went down to Italian Francesca Schiavone, and Swiss number 13 seed Patty Schnyder was beaten by Austrian Sybille Bammer.