MELBOURNE: Kim Clijsters was left reeling from a humiliating Australian Open exit Friday, but fellow Belgian Justine Henin and defending champion Rafael Nadal kept their Grand Slam dreams alive.

A hapless Clijsters was hopelessly out of touch as she was thrashed 6-0, 6-1 in just 52 minutes by Russia's 19th seeded Nadia Petrova.

The reigning US Open champion was not the only top name to crash out, with former world number one Jelena Jankovic also sent packing.

In contrast, Henin performed a great escape act to claw back from a set down to squeeze past Russian 27th seed Alisa Kleybanova 3-6, 6-4, 6-2.

She joined Nadal, Dinara Safina, Andy Murray, Juan Martin del Potro and Andy Roddick in the last 16.

Men's 12th seed Gael Monfils was another casualty as the Frenchman succumbed 6-1, 4-6, 7-6 (7/4), 7-6 (7/5) to American 33rd seed John Isner.

Clijsters, who came into the tournament on the back of winning the warm-up Brisbane International, said she was bewildered by the experience.

"The question is of course is, why? My coach, my fitness coach, are like 'How can something like this happen?'," she said.

"We haven't changed anything really, that's the thing. I was completely off."

The diminutive Henin, the 2004 champion, was also staring at defeat after losing the opening set and falling 3-1 behind in the second to Kleybanova.

But she drew on all her experience as a seven-time Grand Slam champion to bounce back, taking the second set and rattling through the third.

"I kind of survived a little bit today," she Henin, playing in only her second tournament on her comeback from an 18-month retirement.

"It was so difficult for me after the last match. Physically, I suffered a little bit in the last two days. I'm very happy that I'm still in the tournament."

She next plays fellow Belgian Yanina Wickmayer, who beat Italy's Sara Errani 6-1, 6-7 (4/7), 6-3.

Safina, the second seed, clocked a rapid-fire 6-1, 6-2 thrashing of England's Elena Baltacha in her first match on Rod Laver Arena since she imploded during last year's final against Serena Williams.

The Russian took heart from a winning return at the scene of one of her worst days in tennis.

"I didn't have good memories of the last match I played on Rod Laver Arena, for sure," she said. "I am glad to be back and I had to fight hard and make sure I won to forget the bad memories."

She will next face Maria Kirilenko after the fellow Russian outlasted Italy's Roberta Vinci 7-5, 7-6 (7/4).

While Safina and Henin powered on, Jankovic looked like a spent force.

She struggled to live up to her potential in 2009 and her big-match credentials were again found wanting, but Jankovic wasn't concerned.

"It's no big deal, it's only my second tournament of the year," she said.

"I just have to stay positive, keep my head up high."

On the men's side, Nadal was put through his paces by German 27th seed Philipp Kohlschreiber before winning a tense battle 6-4, 6-2, 2-6, 7-5. He will next play Croat Ivo Karlovic who beat countryman Ivan Ljubicic.

Scotland's Murray maintained his flawless form by advancing with a 7-5, 6-1, 6-4 win over Frenchman Florent Serra.

The 22-year-old, who next plays Isner, equalled his best performance here as he takes aim at a maiden Grand Slam title.

"I'm happy to have won in three sets in all of the matches," he said. "I'm happy to save as much energy as possible."

Roddick ground out a 6-7 (4/7), 6-4, 6-4, 7-6 (7/3) win over tenacious Spaniard Feliciano Lopez.

It sets him up with a fourth round clash against Chilean 11th seed Fernando Gonzalez, who beat Kazak Evgeny Korolev 6-7 (5/7), 6-3, 1-6, 6-3, 6-4.

Del Potro fired past German Florian Mayer 6-3, 0-6, 6-4, 7-5.