With one former women's No 1 making an early exit and the current one not playing until today, it was just as well that Kim Clijsters came back to give the Australian Open some first-day luster on a rainy, dreary day at Melbourne Park.

Former top-ranked Maria Sharapova was a surprise 7-6 (4), 3-6, 6-4 loser yesterday to fellow Russian Maria Kirilenko. US Open champion Clijsters, also a former No 1 and making a return to the Australian Open after coming back from retirement, easily won her first-round match 6-0, 6-4 over Canadian qualifier Valerie Tetreault.

It was Sharapova's earliest exit from a Grand Slam since the 2003 French Open and comes after she lost in the second round at last year's US Open.

Showers first delayed the start of play on outside courts yesterday, then forced several suspensions during the day. The first match on Court 6 didn't finish until nearly seven hours after it started.

Clijsters, who won the US Open in September in only her third tournament back from time off to get married and have a baby, is now six tournaments into her comeback but still feeling the nerves that come with playing in a Grand Slam.

"I have the experience from the past, but I haven't been here for so long," Clijsters said. "So I think that's why it all feels new again. So, yeah, the butterflies are there but they're not the same butterflies as the ones when I was 15 where I couldn't sleep the night before a match."

There were no nerves - "just a bad day" - for Sharapova, who was making her first appearance on Rod Laver Arena since winning the 2008 trophy. She missed the Australian Open last year as part of a 10-month layoff due to shoulder surgery, but said her shoulder did not bother her yesterday.

"I could be disappointed or I could just take it as it is and just go back on the court and just keep working," Sharapova said. "I choose option two. A bad day's not going to stop me from doing what I love. I'll be back here on a Saturday of the second week, so you watch."

In first-round men's matches, US Open champion Juan Martin del Potro beat American Michael Russell 6-4, 6-4, 3-6, 6-2 and No 5 Andy Murray defeated South Africa's Kevin Anderson 6-1, 6-1, 6-2. World No 2 Rafael Nadal of Spain beat Peter Luczak of Australia 7-6, 6-1, 6-4.

Zheng wins showdown

Zheng Jie came from a set down to win the all-Chinese showdown with Peng Shuai yesterday to secure her place in the second round.

Zheng, who has slipped down the rankings to 35 after abandoning the Chinese state sports system to manage her own career, was in disarray during the first set, crashing 0-6 before recovering to take the next two sets, 6-1, 6-2.

With rain forcing delays on the outside courts, Zheng said she was slow to start because of a disrupted warm-up routine.

"I had to stop for 30 or 45 minutes and when I got to the court I didn't feel warmed up for the first set," said Zheng, who made the fourth round last year and is one of Asia's best hopes here along with fellow Chinese Li Na.