Conquering his greatest foe in a five-set classic, Federer shifted the narrative in their legendary rivalry. His Grand Slam record and argument to be the greatest of all time now look impenetrable.
Finally breaking free from Nadal's control, Federer bested the Spaniard at a major for the first time since the 2007 Wimbledon final. Nearly a decade of futility, ended with one heroic performance.
No other player has tested Federer mentally or physically over the years like Nadal, who entered Melbourne with a 23-11 edge in their head-to-head series. Most of their matches generally followed the same script: Federer throwing the kitchen sink offensively at Nadal, who'd inevitably wear him down in long rallies by targeting his backhand with vicious spin and staving off break point after break point.
Nadal became Federer's kryptonite early in their rivalry, a hurdle the size of the Swiss Alps.
Before Sunday, their last meeting in a Grand Slam final occurred at the 2011 French Open. With both players dealing with injuries and subtle decline in the intervening five years, no one knew if they'd ever have another chance to battle for a championship. But somewhat miraculously, they would. That long wait only added to the enormity of the situation as the two titans stepped on the court for Fedal XXXV.
With Federer, 35, and Nadal, 30, getting older, this one took on extra stakes.
Nadal came into the final in search of his first Grand Slam title in almost three years. For Federer, that drought dated back further, to Wimbledon in 2012. A win for either man could alter the record books forever.
Federer seized the moment.
From the opening ball, he served beautifully. Dropping 20 aces to Nadal's four and winning 76 percent of his first serves, he also saved 13 of 17 break points. Federer, in a surprise twist, actually outperformed Nadal on the return, converting six of the 20 break points he generated.
The clear aggressor, the Swiss Maestro did something he'd never done against Nadal before: beat him with his backhand. According to data from Tennis Abstract's Jeff Sackmann, Federer's efficiency from that wing far surpassed any he'd mustered in previous Grand Slam meetings with Nadal.
But that's not all: Federer surprisingly outmuscled his archenemy in a deciding set.
So often in the past, with the 2008 Wimbledon and 2009 Australian Open finals notable examples, Nadal and his punishing style managed to outlast Federer in these types of matches. He usually gains an extra wind while Federer levels off. Not this time.
Down 1-3 in the fifth and staring at more Grand Slam heartbreak, Federer didn't panic. He took control of the rallies, using his surprisingly lethal backhand to rein winners or keep Nadal off-guard. Breaking him twice, Federer reeled off the last five games for a 6-4, 3-6, 6-1, 3-6, 6-3 win.
Vacillating between tears and screams of joy, Federer's emotions erupted like a volcano as his accomplishment sank in.
"This one is definitely a milestone in my career, there's no doubt about it," Federer said, according to USA Today's Sandra Harwitt. "He's caused me the most problems in my career. Rafa definitely has been very particular in my career; I think he made me a better player. It remains for me the ultimate challenge to play against him."
One match doesn't change the fact Nadal still owns a comfortable lead in their rivalry. But this victory gives Federer a huge trump card if it's indeed the last time they meet in a major final.
Had he lost, Federer's lead over Nadal in the Grand Slam titles race would've shrunk to 17-15. Instead, it widened 18-14, a margin that will almost assuredly be too great for Nadal—or anyone—to surpass.
The oldest Grand Slam champion in 45 years, Federer's fifth Australian Open crown earned him another achievement: becoming the first man to ever win five or more titles at three separate majors.
Impressive as all those accomplishments are, what's equally incredible is that Federer even found himself in this situation. His 2016 season was derailed by a left-knee injury at the start of the year, and he stepped away after Wimbledon to recover, skipping the Olympics and U.S. Open for the sake of his long-term health. The 2017 Australian Open, therefore, marked his first official tournament in six months.
Many people—probably even Federer himself—tempered their expectations, figuring he'd need a few months to get rid of the rust. Stretched to four sets in the first round against Jurgen Melzer, Federer overcame a shaky start and never looked back.
Ranked 17th because of his extended absence, Federer found himself with a difficult draw. And he navigated it like a magician. Helped by the early exits of defending champion Novak Djokovic and No. 1 Andy Murray, Federer beat four top-10 players—Tomas Berdych, Kei Nishikori, Stan Wawrinka and Nadal—en route to the title, the first man to do so in 35 years.
"I thought I could possibly be dangerous for a top guy, maybe beat one, and then that would probably be it, because the body would probably start aching, which it did, or my level would drop, which it didn't," Federer told the Associated Press (h/t Tennis.com). "That was a big surprise to me, that my level was consistent."
Requiring five sets in three of those matches, Federer battled a leg injury throughout the event. His aging body overlooked the pain as he willed himself to an unexpected triumph.
This moment is the one Federer's searched for in vain the last five years. Watching as other players won Grand Slam titles, Federer's unquenchable thirst for an 18th never wavered. It didn't matter if others doubted him: he believed.
When Federer closed out Nadal and lifted that trophy, relief washed over his face. All the tension that bottled up inside him to win another major poured out as he soaked in the moment. At long last, his journey was complete.
"I waited for the French Open," Federer said to CNN's Ravi Ubha. "I tried. I fought. I tried again and failed. Eventually, I made it. This feels similar."
His sweetest win? Given the circumstances, this just might be.
By winning the Australian Open, Federer added yet another awe-inspiring chapter to his story. Based off how well he played, his Grand Slam window remains open.
Let the quest for 19 begin.
All statistics are courtesy of ATPWorldTour.com unless otherwise noted.
Joe Kennard is a Featured Columnist for Bleacher Report.