Nadal sets up Murray blockbuster as Henin marches on

Defending champion Rafael Nadal set up a blockbuster Australian Open quarter-final with Andy Murray on Sunday while Justine Henin's fairytale comeback stayed on track.

But the tournament ended for US Open champion Juan Martin del Potro and French Open champion Svetlana Kuznetsova.

Zheng Jie, meanwhile, rewrote the history books by becoming the first Chinese player to reach the last eight in Melbourne.

Spain's second seeded Nadal was put to the test by big-serving Croat Ivo Karlovic, who slammed down 28 aces, before he muted the challenge 6-4, 4-6, 6-4, 6-4.

It ensured an enticing last eight showdown with in-form fifth seed Murray after the Scot tamed another big-server, American John Isner, 7-6 (7/4), 6-3, 6-2.

"Murray is one of the more dangerous players on the tour, he can play aggressively and defensively," said Nadal, who has not won a tournament in eight months after being hampered by injury.

"I will have to play as well as I can and use my forehand."

Murray will be competing in his first Australian quarter-final and is the first Briton since John Lloyd in 1985 to get this far.

He showcased his exciting strokeplay against Isner and has yet to drop a set in his four victories at the year's opening Grand Slam.

"I'm playing well. No question about that," said Murray, who lost to Nadal in five sets in the fourth round of the 2007 Australian Open.

"I just need to play like I have been and maybe a bit more if I want to win the tournament."

The pair have played each other nine times with Nadal winning seven.

Henin's successful return to tennis after an 18-month retirement continued full steam when the seven-time Grand Slam champion beat fellow Belgian and world number 16 Yanina Wickmayer 7-6 (7/3), 1-6, 6-3.

"It's a great feeling to be back, everything is going so well," said Henin, who is playing her first Grand Slam since the Australian Open in 2008 after being handed a wildcard by organisers.

"Physically, it's tough as I didn't play for two years, but I love being back on court."

Her victory matched the best performance by a wildcard here in the Open Era -- Martina Hingis in 2006 and Jelena Dokic in 2009 also made the quarters -- and earned her a crack at Russian Nadia Petrova for a place in the semi-finals.

Petrova, the 19th seed, made the last eight by beating third seed Kuznetsova, continuing her giantkilling ways having already ousted Kim Clijsters.

She won 6-3, 3-6, 6-1 and Kuznetsova admitted she deserved to lose.

"It's very disappointing because I thought I played very well in preparation," she said.

"I was struggling a little bit, I was not good today. I think I deserved to lose."

Zheng's achievement was impressive, with the unseeded 26-year-old upsetting Ukrainian 31st seed Alona Bondarenko 7-6 (7/5), 6-4 as she and Li Na, who plays her fourth round match on Monday, continue to fly the flag for China.

The victory sets her up against either second seed Dinara Safina or fellow Russian Maria Kirilenko.

Zheng proved to be marginally steadier than the Ukrainian in a match where both women struggled to hold their serves.

"I think Australia is lucky for me because I won my first Grand Slam doubles title in Australia (with Yan Zi)," Zheng said.

"I'm also so happy I'm in the quarter-finals."

Argentina's del Potro crashed out of contention in a five-set epic with 14th seed Marin Cilic.

The Croatian outlasted an exhausted del Potro 5-7, 6-4, 7-5, 5-7, 6-3 to earn himself a quarter-final against either American seventh seed Andy Roddick or former finalist Fernando Gonzalez of Chile.