A dazed and confused Maria Sharapova survived a melting at the Australian Open on Tuesday when players struggled to last the distance in sweltering conditions.

An under-prepared Lleyton Hewitt needed the backing of the home crowd to also reach the second round after a five-set thriller went well into the early hours.

Russia's Sharapova squeezed past France's Camille Pin 6-3, 4-6, 9-7 after coming within two points of becoming the first women's top seed to go out in the opening round in Melbourne since Romania's Virginia Ruzici in 1979.

With the on-court temperature exceeding 50 degrees, all unstarted matches were suspended on the outside courts. But under the rules, players already on court have to play on and finish their matches.

"It's inhuman to play three hours in that kind of heat," said Sharapova, who took a medical time out following a 10-minute heat break and let a 5-0 lead in the final set slip through her fingers.

"I don't think our bodies were made to do that. When it's that hot your mind doesn't work properly."

Fears of a repeat of the clashes between Serbs and Croats that marred the opening day of the grand slam failed to materialise on Tuesday.

The match between Serbia's Ilia Bozoljac and Croatian Marin Cilic took place amid heavy security and was completed without any problems as troublemakers stayed away from the grounds.

KEEP COOL

Sharapova could scarcely believe the scrap she had been drawn into under the blazing sun.

Trying to keep cool during the changeovers, Sharapova wrapped an ice-filled tube round her neck and chest to fend off the punishing heat.

At 6-6 in the third set, a delirious Sharapova looked completely out of sorts as she plopped down serves and had to be reminded by the umpire that there was no tiebreak in the decider.

"I thought that it would really suck if I lost," the US Open champion said. "But I'm not a quitter."

The roof was closed on the Rod Laver Arena under the extreme heat rules following the conclusion of Sharapova's match.

Belgium's Christophe Rochus and Janko Tipsarevic of Serbia became the latest players to drop out because of the conditions.

Rochus withdrew from his match against Sebastien Grosjean with breathing difficulties while Tipsarevic also blamed the heat after he ran out of puff in the final set against eighth seed David Nalbandian.

BETTER CONDITIONS

"I was tired from the first point. It's not tennis any more, it's who is going to last longest in the sun," said Tipsarevic.

Rafael Nadal had the fortune to play under a closed roof and proved he had done his homework as he blunted American Robert Kendrick's challenge with a 7-6, 6-3, 6-2 win.

Scenting a famous victory, Pin bounded up and down the court and grabbed a break for a 7-6 lead as Sharapova dropped her serve to love with a double fault.

However, Pin's lack of experience on the big stage finally caught up with her and Sharapova won the next three games.

The second seed had to claw back from two sets down the last time the duo met, at Wimbledon in 2006, but on Tuesday he maintained control throughout.

"Wimbledon was a great match but today it was unbelievably hot and the court was a bit slower so the conditions were better for me," the Spaniard said.

Hewitt was lucky to keep alive Australia's chances of ending their search for a first home-grown men's champion since 1976. He fought tooth-and-nail for a 3-6, 2-6, 6-3, 6-3, 6-3 win over American qualifier Michael Russell.

Hewitt's former fiancee Kim Clijsters showed there was no room for sentiment as she began her final fling at the tournament before retiring later this year.

A clubbing forehand ended a 44-minute, 6-0, 6-0 ordeal for hapless Russian teenager Vasilisa Bardina.

Andy Murray almost mimicked Clijsters's ruthless streak when he humiliated Spain's Alberto Martin 6-0, 6-0, 6-1.

The 15th-seeded Scot won the first 17 games before Martin stole a consolation game, leaving Murray to just miss out on the first grand slam triple bagel since 1993.

Martina Hingis was almost as emphatic in a 6-0, 6-2 win over Nathalie Dechy.