There was no scattering of seeds at Melbourne Park on Friday as they obstinately refused to budge, crushing all beneath them at the Australian Open.

Giant-killers have been in short supply at the year's first Grand Slam and so it continued on day five with champion Serena Williams [Images] and top seed Justine Henin [Images] slicing their way through to the fourth round.

• Images from Day 5

They were joined by fifth seed Maria Sharapova [Images], number three Jelena Jankovic, men's second seed Rafael Nadal [Images] and number four Nikolay Davydenko on a bad day for the bookmakers.

Henin advanced without by beating tricky Italian Francesca Schiavone 7-5, 6-4.

"Francesca is always a tough player, tough opponent, and I knew that," the top seed told reporters. "I knew it was going to be a good fight."

Henin, who has now won 31 consecutive matches since losing in last year's Wimbledon semi-finals to Marion Bartoli, meets Hsieh Su-wei for a place in the quarters after the Taiwanese player ousted France's [Images] Aravane Rezai.

Williams eased through with a routine 6-3 6-4 win over Victoria Azarenka of Belarus.

NAGGING INJURIES

Next up for her is 12th-seeded Czech Nicole Vaidisova who ousted Japan's [Images] Ai Sugiyama.

Jankovic shrugged off fatigue and nagging injuries to beat Virginie Razzano 6-2, 4-6, 6-1.

She will face the winner of the night match between Amelie Mauresmo and Australia's Casey Dellacqua.

Sharapova swatted aside identikit opponent Elena Vesnina 6-3, 6-0.

"I thought I made a really good job of stepping up and doing a good job," Sharapova smiled.

Elena Dementieva will hope to make more of a dent in Sharapova next. The Russian 11th seed pummelled 17th-seeded Israeli Shahar Peer 6-2, 6-0.

Davydenko slipped through to the fourth round and revelled in his relative anonymity -- he is yet to play on the main showcourt despite his high ranking.

"I don't think about centre court for me now," the Russian told reporters after beating Marc Gicquel of France 6-3, 6-2, 6-3.

"I know I need to win four matches to be in the quarter-finals -- and I'll be on the centre court." Compatriot Mikhail Youzhny is next for him.

Nadal shrugged off a slow start to beat Frenchman Gilles Simon 7-5, 6-2, 6-3.

The Spaniard trailed 5-2 in the first set to an inspired Simon, who wasted six set points, but he dug deep to win it and then ran away with the match. He next plays 23rd seed Paul-Henri Mathieu of France or Austrian Stefan Koubek.

American Andy Roddick [Images] ends the day's entertainment with a third-round match against German Philipp Kohlschreiber.

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