MELBOURNE, Australia — Andy Roddick outlasted Fernando Gonzalez of Chile to survive a Sunday of upsets at the Australian Open that resulted in fourth-round exits for U.S. Open champion Juan Martin del Potro and two of the top three women.

The seventh-seeded Roddick rallied to beat Gonzalez 6-3, 3-6, 4-6, 7-5, 6-2 and advance to the quarterfinals at the season's first major for the sixth time in eight years. He'll next meet No. 14 Marin Cilic, who ousted del Potro in five sets and 4-hours, 38-minutes earlier in the evening.

"I got a little lucky tonight, but sometimes it's better to be lucky than good," said Roddick, who is hoping to end a Grand Slam title drought that dates back to the 2003 U.S. Open.

Two of Russia's top hopes were ousted, but replaced by other Russians in the women's draw.

Second-ranked Dinara Safina retired due to a back problem while she was down 4-5, serving at 30-40 in the first set against Maria Kirilenko, who had ousted 2008 champion and fellow Russian Maria Sharapova in the first round.

No. 3 Svetlana Kuznetsova lost 6-3, 3-6, 6-1 to Nadia Petrova, who went into the match after a stunning, 6-0, 6-1 third-round victory over U.S. Open champion Kim Clijsters.

While the seeded players dropped, former No. 1 Justine Henin continued her run in her first Grand Slam tournament in two years with a 7-6 (3), 1-6, 6-3 win over fellow Belgian Yanina Wickmayer, keeping her on track for a quarterfinal meeting with Petrova.

Del Potro had an upset win over top-ranked Roger Federer in the U.S. Open final last September, ending the Swiss star's streak of five straight titles in New York.

The 21-year-old Argentine was the first man since Novak Djokovic won the 2008 Australian Open to interrupt the Federer-Rafael Nadal domination of men's Grand Slam titles, and started the season's first major seeded fourth.

The other leading men are still here.

Defending champion Nadal and Andy Murray held off two of the tallest men and biggest servers in tennis earlier on Rod Laver Arena to set up a quarterfinal match up.

Nadal, who beat Federer in the 2009 final, had a 6-4, 4-6, 6-4, 6-4 win over 6-foot-10 Ivo Karlovic of Croatia, the tallest man on the tour.

No. 5 Murray overcame 6-foot-9 American John Isner 7-6 (4), 6-3, 6-2 to reach the final eight in Australia for the first time. The 22-year-old Scot hasn't dropped a set in four matches.

No. 1 Federer and No. 3 Djokovic play their fourth-round matches Monday.

Former No. 1 Roddick looked out of it with the Chilean on a roll, leading by two sets to one and only a point from forcing a tiebreaker that would have been a lottery between the two big servers.

But the American won five straight points to level the sets at 2-all and broke early in the fifth to dictate the ending.

"When Fernando gets hot, you know that a lot of the match is out of your control," Roddick said. "I think the thing that helped me was being able to serve through."

Gonzalez saved four set points in the 10th game of the fourth set. After Gonzalez led 40-0 on serve, Roddick then won four straight points to get another set point.

He clinched it with a forehand down the line, which a line umpire initially ruled out.

Roddick asked for a video replay, which showed the ball hit the line. The set was awarded to the American, amid protests from Gonzalez that he could have had a play on the ball but stopped when he heard the out call.

Gonzalez then kicked two drink bottles near the player's chair. The booming forehands that troubled Roddick earlier then started to wilt and, after saving two match points, the Chilean double-faulted to end the match.

The 2007 Australian Open finalist refused to blame one disputed call for turning the match, saying he'd have to watch replays before commenting further.

"But it wasn't the key of the match," he said. "The key of the match was before I have like a breakpoint, love-30, miss two balls. I think that was most important than that point.

"We played more than 200 points. It was important, for sure, but it wasn't the key of the match."

Roddick said the knee problem that sidelined him at the end of last season was bothering him a bit, but it didn't affect the game.

When del Potro asked if the wrist problem that flared last week had troubled him against Cilic, the Argentine replied that he couldn't tell because his whole body hurt.

Safina said her movement was so restricted she could barely move, and wouldn't even be able to pack her bags to leave.

Safina, the 2009 Australian finalist who held the No. 1 ranking despite never winning a major, limped off when facing set point.

"It was getting worse and worse, I have no idea how it happened. It was really terrible," said Safina, who saw her season last year end prematurely because of a back problem. "I turned to my coach and I said I cannot move anymore. It's shocking."

In an afternoon match, 2008 Wimbledon semifinalist Zheng Jie set another national mark by becoming the first Chinese player to reach the quarterfinals at Melbourne Park with a 7-6 (6), 6-4 victory over Alona Bondarenko. She next plays Kirilenko.

Henin, who is unranked and playing on a wild-card entry in her second tournament since returning from a 20-month retirement, told the crowd she'd missed tennis too much to resist a comeback.

The seven-time Grand Slam winner dominated the first-set tiebreaker after saving three set points in the 12th game. After dropping the second set, Henin broke Wickmayer's serve to open the deciding third set and was on top after that.

"It's been great moment for myself," Henin said. "It's a great feeling to be back, been a great fight and thank you."