MELBOURNE, Australia -- Switzerland's Martina Hingis and Venus Williams and Monica Seles of the U.S. made easy advancements to the quarterfinals in the Australian Open on Sunday -- all winning their fourth-round matches Sunday in less than an hour.

	Monica Seles is chasing her fifth Australian Open title.

Hingis demolished South Africa's Amanda Coetzer 6-1, 6-0 to book her place in the quarterfinals of the Australian Open.

Williams powered into the quarterfinals when she crushed Bulgarian Magdalena Maleeva 6-0, 6-3 with her most convincing performance of the tournament.

Monica Seles advanced quickly when Anabel Medina Garrigues wrenched her knee trying to reach a wide shot and had to retire.

Hingis, the former top-ranked player in the world, needed just 44 minutes to seal one of her easiest ever victories on the Melbourne Park center court.

Hingis, appearing in only her second tournament since ankle surgery last October, outplayed 15th-seeded Coetzer in every department in a match that once again exposed the lack of depth in women's tennis.

The 21-year-old Hingis lost only 24 points in the entire match and is yet to drop a set in the tournament. She has lost just two games in her last two matches.

"I really have the belief I can go all the way and that's a nice thing to have," Hingis said.

"I played really well," Hingis said. "I've played her in the past and lost to her, so I knew I would have to play well to beat her.

"Every game I play I'm feeling better. I'm more secure in my shots and I'm taking my chances."

Hingis won five grand slam titles, including three consecutive Australian Opens, as a teenager but hasn't won a major in three years.

She lost her No. 1 ranking last year when she tore three ligaments in her left ankle, but has made a strong return to the game, winning the Adidas International last weekend to warm-up for the Australian Open.

"I was feeling well coming into this tournament after winning in Sydney last week," she said.

"I played better than I expected to after the operation. I've been pushed enough in the past so it's nice to have matches like this."

She plays Adriana Serra Zanetti in the quarterfinals after the unseeded Italian beat Slovakia's Martina Sucha 6-1, 7-5.

Maleeva, the 13th seed, had no answer to Williams, the reigning Wimbledon and U.S. Open champion, and her all-round strength and succumbed in a fourth-round match lasting only 48 minutes.

"I think that my game can keep going up," Williams warned.

"This is very good for me...especially seeing as I've been little bit injured I felt very good."

An overwhelming favorite to claim her first Australian Open title, the second-seeded Williams again took to the court with her left knee strapped but showed few signs of the tendinitis that had hindered her campaign early in the tournament.

Williams started relatively slowly and had two break points against each of three service games in the first set.

But she got herself out of trouble with ease and brushed Maleeva aside to race through the set in a mere 19 minutes.

Maleeva earned a big cheer from the crowd when she won her first game of the match in the second game of the second set. But Williams broke easily two games later and then shut Maleeva out with unplayable winners to all parts of the court.

"You try not to limit yourself on what you can do ... just keep serving well, coming in, do my personal best," she said.

Williams will play Seles in the quarterfinals.

Williams' victory denied Maleeva a unique piece of Open history. The Bulgarian had been hoping to upset Williams to complete a unique family treble by joining elder sisters Katerina and Manuela as Australian Open singles quarterfinalists.

Seles, a four-time Australian Open champion, needed two games to figure out her opponent's style, and then began pushing her around relentlessly.

She reached 4-2 on the point where Medina Garrigues stepped awkwardly on her right foot while running for a backhand in the corner, skipped once and fell to the court, her face contorted in pain.

After several minutes' treatment by the trainer, on court and then at her chair, Medina Garrigues declined a knee brace and returned to the baseline, skipping lightly as she prepared to receive service.

But she immediately started limping again trying to reach the first shot. On the next, she returned serve but could only watch as Seles sent a forehand down the line.

In tears, she gave up, accepted an ice bag for her sprained knee and walked off, leaving Seles the winner in just 33 minutes.

"She probably is playing the best tennis of her career. It's just a tough situation," Seles said of the 19-year-old Spaniard, who rose from No. 114 at the end of 2000 to No. 45 now.

"I finally got a little bit of control of the match," Seles added. "I think some of the best tennis was ahead of us."

Reuters and The Associated Press contributed to this report.