Swiss roll on while rest toil in Melbourne heat

Roger Federer and Martina Hingis kept their cool to reach the fourth round of the Australian Open yesterday when scorching heat forced one teenager to retire and organisers to protect the players.

Federer, the overwhelming favourite to win the men's singles, brushed past Max Mirnyi of Belarus 6-3 6-4 6-3 in a night match to reach the last 16 without dropping a set.

"I haven't got any injuries, I'm playing good tennis and I'm happy, so it's all good," the world number one said in a courtside interview.

His Swiss compatriot Hingis, a former world number one, continued her remarkable return to grand slam tennis by crushing Czech Iveta Benesova 6-4 6-1 under a blazing sun.

Officials closed the retractable roofs on the two main stadiums and postponed matches on the outside courts under their extreme heat policy after Michaella Krajicek retired from her match suffering heat stress.

The Dutch teenager lost the first set 6-2 to third seed Amelie Mauresmo and decided not to continue after calling for assistance.

"I felt like I was going to throw up," Krajicek said. "I just couldn't even see the ball because my eyes were burning very much.

"I don't like to give up matches, that's for sure. I never give up... but I couldn't play any more."

Argentine sixth seed Guillermo Coria also wilted in the blazing sun, losing 6-2 6-2 3-6 6-4 to France's Sebastien Grosjean before the extreme heat policy was invoked.

Grosjean, seeded 25th, now faces compatriot Paul-Henri Mathieu in the fourth round after the 24-year-old beat Peru's Luis Horna 7-6 7-6 6-1.

There was better news for Belgian Kim Clijsters, who has struggled all week with hip and back injuries. The world number two and US Open champion showed no obvious signs of problems as she romped to a 6-1 6-2 victory over Roberta Vinci.

"I'm still not moving like I normally can, but it's a lot better," Clijsters said.

The Belgian will play Italy's 15th seed Francesca Schiavone in the fourth round after she thrashed Maria Sanchez Lorenzo 6-0 6-0, handing the Spaniard a dreaded "double bagel".

Argentina's Juan Ignacio Chela followed up his stunning win over local favourite Lleyton Hewitt with a 6-1 6-4 6-4 victory over Belgium's Kristof Vliegen to set up a fourth round clash with Nicolas Kiefer.

The German beat Spanish baseliner Juan Carlos Ferrero, the 15th seed, 6-3 6-2 5-7 6-2.

Slovakia's Dominik Hrbaty lived up to his reputation as the ironman of tennis, winning his third straight five-set match 1-6 6-4 6-3 2-6 6-4 over Russia's Igor Andreev.

He will play fifth seed Nikolay Davydenko after the lanky Russian beat local wildcard Nathan Healey 6-2 5-7 6-4 7-5 to knock the last Australian out of the men's draw.

In-form German Tommy Haas beat another Australian wildcard Peter Luczak 4-6 6-3 6-4 6-4 earlier in the day to earn the dubious honour of playing Federer.

"It looks like it's going to be a walk in the park, but it's definitely not going to be that," Federer said. Haas beat the Swiss at the pre-Open Kooyong invitational tournament last week.

Myskina keeps Russian charge

Twelfth seed Anastasia Myskina continued the Russian charge through the women's draw by brushing aside Sweden's Sofia Arvidsson 6-3 6-1.

Myskina is the fifth Russian woman to reach the fourth round where she will play seventh seed Patty Schnyder of Switzerland who beat Japan's Aiko Nakamura 6-2 6-3.

France's Mauresmo, beaten by Hingis in the 1999 Australian Open final, will play Czech Nicole Vaidisova after the 14th seed beat Italian Flavia Pennetta 6-4 6-2.