MELBOURNE, Australia >> So here was Roger Federer, down a break in the fifth set in a Grand Slam final. Across the net was his nemesis, Rafael Nadal, the left-handed Spaniard he hadn’t been able to beat in a major final in almost a decade.

The 35-year-old father of four was back in his first tour-level tournament after six months off letting his injured left knee recover, and he hadn’t won any of the big four events in tennis since Wimbledon 2012. Nadal was returning from injury, too, and somehow the pair had renewed the Roger-Rafa rivalry in a throwback Australian Open final that transcended sport.

At that moment, an 18th Grand Slam title didn’t feature in Federer’s thinking.

Don’t play the player, he reminded himself, just play the ball. Attack the serve.

With that, Federer recovered the break, and seized momentum in a roll of winning 10 consecutive points that helped propel him to a 6-4, 3-6, 6-1, 3-6, 6-3 win late Sunday night. His fifth Australian title extended his buffer to four atop the list of all-time Grand Slam champions. Nadal remained tied with Pete Sampras in second place with 14.

“For me it’s all about the comeback, about an epic match with Rafa again,” Federer said, “… that I can still do it at my age after not having won a slam for almost five years.

“That’s what I see. The last problem is the slam count — honestly, it doesn’t matter.”

Federer had lost six of the previous eight Grand Slam finals he’d played against Nadal and was 11-23 in their career meetings. His last win over Nadal in a major final was at Wimbledon in 2007.

“It remains for me the ultimate challenge to play against him,” Federer said. “It’s super sweet, because I haven’t beaten him a Grand Slam final for a long time now.

“This one means a lot to me because he’s caused me problems over the years.”

With big wins come big celebrations, Federer said. “We’re going to party like rock stars tonight.”

By winning in Melbourne, where he first played in 2000 and where he kicked off his long reign at No. 1 with the title in 2004, he became the oldest man since Ken Rosewall in 1972 to win a slam.

Federer had lost five semifinals in Australia since winning his previous title here in 2010. He’d lost three major finals since winning that last Grand Slam in 2012. He hadn’t played Nadal in a major final since losing at the French Open in ‘11.

After twice rallying from a set down, Nadal was a break up in the fifth but couldn’t hang on to become the first man in the Open era to win each of the four majors twice. Instead, Federer became the first man in the Open era to win three of Grand Slam events at least five times (7 Wimbledon titles, 5 U.S. Opens, 5 Australian Opens and 1 French Open).

“The magnitude of this match is going to feel different. I can’t compare this one with any other one except for maybe the French Open in ‘09,” Federer said. “I waited for the French Open, I tried, I fought. I tried again and failed. Eventually I made it. This feels similar, yeah.”

Three months ago, Federer and Nadal were in the Spaniard’s native Mallorca for the opening of a tennis academy wondering if they’d ever be able to contend for majors again.

Yet here they were, the first Grand Slam tournament of the season, renewing the classic rivalry that saw them dominate tennis a decade ago.

The long-odds final — No. 9 against No. 17 — unfolded after six-time champion Novak Djokovic was upset by No. 117-ranked Denis Istomin in the second round and top-ranked Andy Murray, a five-time losing finalist in Australia, went out in the fourth round to 50th-ranked Mischa Zverev.

Federer beat Zverev, and then U.S. Open champion Stan Wawrinka in a five-set, all-Swiss semifinal. That was the night before Nadal held off Grigor Dimitrov in an almost five-hour, five-set semifinal late Friday.

After four sets of a final where the momentum alternately swung, the fifth had all the tension and drama that these two players are famous for.

Federer had a medical time out for treatment on his upper right leg and was broken in his first service game of the deciding set.

But he rallied and put Nadal under pressure. Nadal saved three break points in the eighth game but lost momentum again when Federer finished off a 26-shot rally — the longest of the match — with a forehand winner down the line.

Federer got the pivotal break for 5-3, but Nadal made him work for the very last point.

Serving for the match, and after saving two break points, Federer was called for a double-fault at deuce. He challenged the out call on his second serve, however, and it was overturned. Tempo back in his court.

After hitting a forehand crosscourt winner on his second match point, his celebrations were delayed when Nadal challenged the call.

Federer watched the replay, and leaped for joy when it showed his last shot was in — the perfect finish to his 100th match at the Australian Open.

“Congratulation to Roger … Just amazing, the way he’s playing after such a long time of him not being on the tour,” Nadal said. “For sure, you have been working a lot to make that happen.”

“I fight a lot these two weeks,” he added. “Today, a great match, probably Roger deserved it a little bit more than me.”

Federer’s championship victory capped a remarkable weekend for 30-somethings — all four singles finalists were 30 or older — after 35-year-old Serena Williams beat her older sister, Venus, in the women’s final to capture her Open-era record 23rd Grand Slam title.