MELBOURNE, Australia (AP)—Four days after an angry outburst over the rules relating to replays and line calls, Andy Roddick got a crucial call in his favor in his fourth-round Australian Open win over Fernando Gonzalez.

Roddick held off the 2007 Australian Open finalist 6-3, 3-6, 4-6, 7-5, 6-2 on Sunday to advance to the quarterfinals at the season’s first major for the sixth time in eight years.

The 27-year-old American will meet No. 14 Marin Cilic of Croatia, who ousted U.S. Open champion Juan Martin del Potro in five sets.

Roddick bucked the trend on a day of upsets that also resulted in fourth-round exits for two of the top women: No. 2 Dinara Safina, last year’s runner-up, and No. 3 Svetlana Kuznetsova, the reigning French Open champion.

“I got a little lucky tonight, but sometimes it’s better to be lucky than good,” said seventh-seeded Roddick, who hopes to end a Grand Slam drought that dates to the 2003 U.S. Open.

After wasting four set points in the 10th game of the fourth set, Roddick rallied from 40-0 down in the 12th—Gonzalez’ next service game—to earn a fifth set point. Then he hit the contentious, dipping crosscourt forehand.

The ball was called out and Gonzalez didn’t take a swing. Roddick challenged the call immediately, and the evidence showed that the ball just caught the line, giving Roddick the set to level at two-all and igniting a protest from Gonzalez.

The Chilean argued that he could have had a play on the ball and that chair umpire Enric Molina should have replayed the point.

“In my opinion you could not have reached the ball,” Molina told Gonzalez in Spanish.

Gonzalez strode back for the changeover, kicking two water bottles and a courtside chair before slumping into it. The entire episode had a similar feel to the end of Roddick’s second-round win over Brazilian Thomasz Bellucci, when he angrily objected to a decision that went against him on a match point.

After reviewing a TV replay of that point following his match Wednesday, Roddick apologized and said his interpretation, on reflection, may not have been correct.

After seeing Gonzalez’ reaction late Sunday night, Roddick said he still didn’t understand how the rule is applied as to when a point gets replayed.

“I know he was pretty upset about the challenge and that rule no one seems to know about,” Roddick said. “I can certainly sympathize with his frustrations, you know?”

Gonzalez refused to blame one disputed call for turning the match.

“We played more than 200 points,” he said. “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.

Safina had to retire because of the recurrence of a back injury when she was serving at 5-4 down and 30-40 in the first set against Maria Kirilenko, who had knocked 2008 champion Maria Sharapova out of the tournament in the first round.

Safina said her back hurt so much she could barely move.

“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.”

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.

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 stay away.

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

In an afternoon match, 2008 Wimbledon semifinalist Zheng Jie became 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.

Del Potro, the first man since Novak Djokovic won the 2008 Australian Open to interrupt the Roger Federer-Rafael Nadal domination of men’s Grand Slam titles at the U.S. Open in September, started the season’s first major seeded fourth and among the hot favorites.

When del Potro was asked if the wrist problem that flared last week had troubled him against Cilic, the 21-year-old Argentine replied that his whole body hurt.

The other leading men are still here.

Defending champion Nadal and No. 5 Andy Murray held off two of the tallest men and biggest servers in tennis 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, while 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.

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

Federer will take on Lleyton Hewitt, aiming to extend a run of making the semifinals or better every year since winning the first of his three Australian titles in 2004.

He is on a 14-match winning streak against former U.S. Open and Wimbledon champion Hewitt, who is bidding to become the first Australian man to win the national title since 1976.

Defending champion Serena Williams takes on another Australian, No. 13 Sam Stosur, in a late afternoon match at Rod Laver Arena. Her sister, sixth-seeded Venus Williams, opens proceedings against Italian Francesca Schiavone on the same court.