MELBOURNE, Australia -- Former No. 1 Andy Roddick overcame 2007 Australian Open finalist Fernando Gonzalez of Chile 6-3, 3-6, 4-6, 7-5, 6-2 on Sunday, surviving to earn a berth in the Australian Open's quarterfinals.
"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.
Gonzalez saved four set points in the 10th game of the fourth set before Roddick finally prevailed in the 12th game on a contentious call.
A line umpire initially ruled that the ball had gone out, and Gonzalez claimed he had stopped when he heard the call.
Roddick asked for a video replay. It showed the ball hit the line, giving Roddick the point and the fourth set.
"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."
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.
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 with the No. 4 seeding and among the favorites.
The four other leading men are still here.
Defending champion Nadal and Andy Murray held off two of the tallest men and biggest servers in tennis on Sunday to set up a quarterfinal meeting.
Nadal 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.
In the previous match at Rod Laver Arena, No. 5 Murray overcame 6-foot-9 American John Isner 7-6 (4), 6-3, 6-2. Murray hasn't dropped a set in four matches.
Del Potro struggled most of the way through the 4-hour, 38-minute match against Cilic, who exacted a measure of revenge with the victory. The 21-year-old Croat lost to del Potro in the fourth round here last year and in the U.S. Open quarterfinals.
Del Potro had been bothered by right wrist pain that forced him out of a warmup tournament and was undoubtedly weary from a five-set, second round win over James Blake -- the longest of the tournament in terms of total games at 62.
He said the wrist and the foot were only part of the problem. What hurt? "The whole body."
The increased expectations on him weren't a bother, he said.
"No, I really enjoyed that pressure. The crowd is unbelievable with me. They support me every match, every point," said del Potro, who plans to go home and recover. "I was down in every match, and they help me to keep fighting, like today. I really like it, that pressure."
When del Potro hit his last backhand long, Cilic sank to both knees, arms in the air. He volleyed the ball high into the stands, where his most vocal supporters were madly cheering.
"Today was my best so far," said Cilic, who converted four of his 16 break-point chances. "Physically I think [del Potro] was tired and he struggled, but I was feeling really good ... and I had some crazy fans."
Nadal only dropped serve once against Karlovic, to surrender the second set. In the third and fourth sets, he broke the Croat in the third games.
He showed plenty of emotion after earning a breakpoint in the third set, screaming out "Vamos!" and spinning around as he ripped his left elbow back and raised his left knee.
"I just wait my chance. Be focused on my serve ... and wait the chance on the return," Nadal said. "I was returning really well when I had the chance to touch the ball."
Murray lost to Federer in the 2008 U.S. Open in his only Grand Slam final to date. He knows he'll probably have to beat Nadal and Federer to claim his first major here. So far, so good.
"I moved really well since the start," Murray said. "I didn't drop a set yet ... not too much to complain about."
Information from The Associated Press was used in this report.