MELBOURNE, Australia — When he needed it the most, top-seeded Roger Federer found an extra gear to survive at the Australian Open.

There was never a letup in the tension of the 4Z\x-hour match as Federer was forced repeatedly to rally before outlasting 49th-ranked Janko Tipsarevic 6-7 (5), 7-6 (1), 5-7, 6-1, 10-8 on Saturday to advance to the fourth round of the tournament he has won the past two years.

Tipsarevic, who has never reached a singles final, played the match of his life and gave Federer everything he could handle with the packed crowd screaming on every point.

"I went on court with the idea that I can win," the Serbian player said. "I was close. I lost because he was better in the important moments of the match."

Federer, seeking his 13th Grand Slam crown, needed every one of his personal best 39 aces — 14 more than his previous mark in one match — to fend off the third-round challenge from the 2001 Australian Open junior champion.

"I don't often get to play five-setters unless they're against Nadal at Wimbledon," Federer said of his rivalry with longtime No. 2-ranked Rafael Nadal. "It was good to be part of something like this. It's a pity you can't have draws in tennis."