Images: Australian Open, Day 1, Melbourne

Rafael Nadal beat the rain and his opponent in a perfect start to his Australian Open defence as Maria Sharapova, Kim Clijsters and Justine Henin enjoyed mixed fortunes on their returns to Melbourne Park on Monday.

Sharapova was the big loser, suffering a shock first-round loss to Maria Kirilenko, but Clijsters and Henin won easily on a day when everything, except Melbourne's fickle weather, followed the usual script.

Second seed Nadal quelled speculation about his fitness with a ruthless 7-6, 6-1, 6-4 victory over Peter Luczak at a packed Rod Laver Arena.

"First rounds are always difficult to play very well," Nadal said.

"I thought (it was) gonna be a tough match. First set was tough. Later was easier."

Instead of the extreme heat that has left competitors soaked in sweat and gasping for air, the opening day of this year's first Grand Slam was severely disrupted by unseasonal wind and showers.

Tournament organisers closed the giant retractable roofs on the two main courts to ensure the featured singles matches went ahead but almost 40 matches on the outside courts were left unfinished or rescheduled for Tuesday.

Juan Martin Del Potro and Andy Murray escaped the downpours to ease through while Dinara Safina, Svetlana Kuznetsova and Elena Dementieva led the Russian charge in the women's draw.

Sania Mirza will have to wait till Tuesday to start her Australian Open campaign as rains forced postponement of her first round match.

The Indian ace was scheduled to play the third match at court No 6 against French 27th seed Aravane Rezai at Melbourne Park.

She will now play the first match of the morning at the same court on Tuesday.

Sania comes into the season-opening Grand Slam after playing warm up events in Auckland, New Zealand and Hobart.

Sharapova, seeded 14th and making her first appearance at Melbourne Park since winning the championship two years ago, lost 7-6, 3-6, 6-4 to her good friend and fellow Russian Kirilenko.

Unable to defend her title last year because of a shoulder injury, Sharapova was a shadow of the player who stormed to the 2008 title without dropping a set, contributing to her own downfall with 66 unforced errors and 11 double faults.

"I could be disappointed or I could just take it as it is and just go back on the court and just keep working. I choose option two," Sharapova said.

Clijsters was runner-up to Henin at the 2004 Australian Open but had given up on the idea of winning the title when she quit the sport in 2007.

She made a fairytale comeback last year by winning the US Open, however, and launched her Australian campaign with a 6-0, 6-4 win over Canadian qualifier Valerie Tetreault.

"I never expected when I said goodbye that I would be back here," Clijsters said.

"Life can change and I changed my mind, and so far I haven't regretted it for a second."

Henin romped past fellow Belgian Kirsten Flipkens 6-4, 6-3 and will play Dementieva after the in-form Russian defeated compatriot Vera Dushevina 6-2, 6-1.

"I feel it's my place to be here," Henin said.

"It's a good feeling to be back here."

Murray began his latest attempt to end Britain's long Grand Slam drought with an impressive 6-1, 6-1, 6-2 victory over South African qualifier Kevin Anderson, while Roddick dusted himself off after colliding with a line judge to defeat Dutchman Thiemo De Bakker 6-1, 6-4, 6-4.

Roddick, back playing after a knee injury, said he initially feared the worst when he crashed into the official and tumbled to the court.

"I promise you that first step afterwards was a relief," the American said

Safina, runner-up in Melbourne last year, defeated Slovakia's Magdalena Rybarikova 6-4, 6-4 despite still trying to rebuild her fitness after suffering back pain late last year.

"At the end of the last year I was tired, exhausted, like I had no more fun on the court," she said.

"But now I feel like I'm back and I'm enjoying every moment."

There was no repeat of the violent ethnic clashes that have marred the start of the tournament in recent years with security adopting a firm stance.

Police ejected 11 spectators for carrying a flare then standing on seats during Croatian Ivo Karlovic's five-set win over Czech Radek Stepanek.

"Security processes and procedures are very tight," police superintendent Jock Menzel said.

"We won't tolerate poor behaviour and we've demonstrated that this morning."