Gunning for a fourth Australian Open title in five years, the top-seeded Hingis faces unseeded Rita Grande of Italy for a spot in the round of eight. Serena Williams, seeded sixth, will face 17-year-old Daja Bedanova of the Czech Republic in a fourth-round encounter.

Venus Williams, who could face either her younger sister or Hingis in the semifinals, looks to extend her winning streak on hard courts to 29 matches when she faces 1999 runner-up Amelie Mauresmo of France, the 13th seed.

On the men's side, fourth seed Magnus Norman of Sweden and former champion Yevgeny Kafelnikov of Russia vie for quarterfinal berths.

Norman, a semifinalist last year, meets No. 16 Sebastien Grosjean of France, and Kafelnikov, seeded fifth, battles unseeded Swede Andreas Vinciguerra.

Hingis has not dropped a set in the first three rounds and is trying for her first major since winning here in 1999. Last year, she went without a Grand Slam singles title for the first time since 1996. Hingis was denied a fourth straight title in Melbourne with a loss to Lindsay Davenport in last year's final.

The 20-year-old Hingis is unbeaten in 10 matches this season after helping Switzerland win the Hopman Cup in Perth and capturing the adidas International last week in Sydney.

Grande defeated Australia's Evie Dominikovic in straight sets on Saturday. She lost to Hingis in their only meeting at Tokyo in 1998.

"Grande is actually one of the players I know a little bit better, I've played her before," Hingis said. "She is a player that I have to take seriously and just play my game."

Like Hingis, Serena Williams has not dropped a set in her three wins and will look to improve on her fourth-round showing here last year.

Bedanova upset ninth seed Elena Dementieva of Russia in three sets on Saturday to earn her meeting with Serena Williams.

Venus Williams, seeded third, has not dropped a set in the last two rounds after going the distance to win her first-round match against a Spanish qualifier.

The reigning Wimbledon and U.S. Open champion has not lost a Grand Slam match since falling to Arantxa Sanchez-Vicario in the quarterfinals of last year's French Open, winning 38 of her last 39 matches since that defeat.

Mauresmo recorded a straight-set victory over former French Open champion Iva Majoli of Croatia on Saturday. She lost to Venus Williams in their only previous encounter here three years ago in the third round.

"I think that will definitely be an important match," Venus Williams said. "She (Mauresmo) likes playing here in Australia, I think she likes the surface and I think basically I want to go out there and play my game and be serious and not take anything for granted."

In the other women's fourth-round encounter, 10th seed and two-time semifinalist Amanda Coetzer of South Africa meets unseeded Paola Suarez of Argentina, who upset seventh seed Mary Pierce of France in the third round.

Norman outlasted Alex Calatrava of Spain in four sets on Saturday. The 24-year-old Swede has reached the fourth round in five of his last six Grand Slam events, including a runner-up showing at last year's French Open.

Grosjean eliminated Thomas Johansson of Sweden in straight sets Saturday to set up his encounter with Norman, who defeated the Frenchman twice last year.

Kafelnikov overcame former NCAA champion Chris Woodruff of the United States in four sets on Saturday, after needing five sets to eliminate Germany's Nicolas Kiefer in the previous round.

The 26-year-old Russian is 16-1 at the Australian Open since 1999, whe he won the title. He was runner-up to Andre Agassi last year.

Vinciguerra, 19, ousted No. 10 Wayne Ferreira of South Africa in four sets to reach the fourth round of this event for the first time.

"I played him a couple of months ago in (the) Stockholm Open and I have quite a bit of an idea what I need to do to get a victory," said Kafelnikov, who defeated the Swede in straight sets at Stockholm last November in their only previous matchup.

In other fourth-round action, No. 15 Arnaud Clement of France battles hard-serving Greg Rusedski of Britain, who upended top seed and world No. 1 Gustavo Kuerten in the second round.

Also, former world No. 1 and 1997 finalist Carlos Moya of Spain, fresh off his five-set triumph over seventh seed Lleyton Hewitt of Australia, goes against unseeded German Rainer Schuttler.

On Sunday, those advancing to the quarterfinals on the men's side were Agassi, fellow American Todd Martin, No. 12 Patrick Rafter of Australia and No. 14 Dominik Hrbaty of Slovakia, who upset second seed Marat Safin of Russia.

For the women, defending champion Lindsay Davenport, four-time champion Monica Seles and No. 12 Jennifer Capriati of the United States, as well as No. 8 Anna Kournikova of Russia all reached the round of eight.