There is a moment immediately after Roger Federer’s final forehand has been confirmed as a winner: Federer beams and raises his arms and leaps in celebration, and then the magnitude of his triumph seems to bear down upon him and his cry of victory becomes a scream as he doubles over, gripped by a joy so intense it looks almost painful. Against all the odds, all expectation, against the man seemingly destined to be his master both on court and perhaps in the history books, Federer had captured his record-extending 18th grand slam title, five years after his last. It’s an achievement that transcends tennis and must be considered among the greatest in sport; with due deference to Ali, Bradman, Nicklaus and Maradona, here’s why Federer’s 2017 Australian Open might just be the best of the lot.

His age

At 35, Federer is the oldest winner of a men’s grand slam title since 37-year-old Ken Rosewall beat 36-year-old Malcolm Anderson to claim the Australian Open in 1972. But Federer is playing in a far tougher era, one widely considered to be the greatest of all time. His three greatest rivals – Novak Djokovic, Andy Murray and of course Rafael Nadal – belong to a different generation: only Feliciano Lopez remains active from Federer’s first Australian Open title in 2004. Rather than slip into retirement like his contemporaries, Federer refined his game, streamlined his schedule and continues to compete at the pinnacle. Absurdly, he’s reached the semifinals or better in the last five Grand Slam tournaments in which he’s entered.

His injury

A reminder: the Australian Open was Federer’s second tournament after a six-month absence from a knee injury. The challenge was not winning the title but reaching the second week. Federer admitted he was unaware his friend and compatriot Stan Wawrinka shared his half of the draw as he hadn’t bothered to look beyond the quarterfinals. Even for a player in their prime, such a victorious comeback would seem an impossible task: at 35 it is simply unheard of.

His opponent

If Federer had beaten, say, Grigor Dimitrov in the final then his tournament would still have been hailed as a tennis miracle. But he beat Nadal, his great rival and closest contender for the mantle of greatest of all time. Winner of 14 grand slams, Nadal is second only to Federer in the record books. Going into the match the Spaniard held a 23-11 winning record over the Swiss, including 9-2 in grand slams. Elderly champions tend to prevail against limited opposition: George Foreman knocking out Michael Moorer is a typical example. Elderly champions do not beat their supposedly-unbeatable nemesis who are five years their junior – at least not until last Sunday.

The rivalry

This victory does far more than bring Federer slam number 18; it reframes his entire rivalry with Nadal, pushes his slam record further out of reach, and solidifies his legacy as the greatest player to ever pick up a racket. The main argument against this legacy was simple: how could Federer be the best ever when Nadal beat him time and time again? Had Nadal won on Sunday, he would have further reinforced this argument and gained within two slams of Federer, with the French Open next to come. Nadal will always hold a winning record over Federer, but Federer won what is likely to be the last major final the pair ever play against each another, one described by Andy Roddick as possibly the most important match in grand slam history. It’s difficult to overstate the significance of that.

The final itself...

The final was a thriller, one that didn’t reach the technical heights of 2008 Wimbledon, but arguably even surpassed the greatest tennis match of all in terms of tension and drama. It’s tempting to describe the fifth set as inevitable – Federer vs Nadal, what do you expect? – but don’t fall into that trap. In their two most recent slam meetings, both at the Australian Open, Nadal had triumphed in four and three. Federer hadn’t beaten Nadal over five sets since 2007: his only chance was assumed to be a rapid victory inside the distance. When Nadal took the fourth, Federer fans feared the worst; when he broke Federer early in the fifth, the game was surely up. We’d seen this film many times before, we all knew how it ended. Instead, Federer tore up the script, pressuring the Nadal serve before reeling off five straight games to snatch away the title. Even the last service game proved a miniature epic, Federer going 15-40 down but refusing to yield to the seemingly inevitable. Even now his victory feels unreal: Federer beat Nadal in a grand slam final. Over five sets. After going a break down in the fifth. That was the opposite of inevitable; that was meant to be impossible.

...And Federer’s route to get there

As well as potentially ending his career, Federer’s enforced injury layoff meant he was seeded 17 for the Australian Open and had to play three Top-10 seeds simply to reach the final. Had any one of Tomas Berdych (10th seed), Ken Nishikori (5) or Stan Wawrinka (4) beaten Federer it would not have registered as a surprise; indeed Nishikori (a decade younger than Federer) and Wawrinka (winner of three grand slams) were both tipped to take out the Swiss veteran. Instead, Federer demolished Berdych, and beat Nishikori and Wawrinka in five sets. His only piece of fortune was the shock defeat of World Number 1, Andy Murray, a prospective quarterfinal opponent: Federer repaid Mischa Zverev, Murray’s conqueror, by thrashing the German in straight sets.

The long wait

Since winning Wimbledon in 2012, Federer had contested three grand slam finals and lost all three to Novak Djokovic. Wimbledon 2014 and 2015, the US Open 2015 offered both hope and despair: even though Federer could still compete at the top, he couldn't get past his younger rival. Even when Djokovic was removed from his path, such as the US Open 2014 and Wimbledon last year, Federer suffered defeat in the semifinals. The final years of his career seemed doomed to be spent in quixotic pursuit of that unreachable 18th slam. To bounce back from so many near misses, five years after his most recent triumph, displays astonishing mental fortitude.

His greatness

Here’s a question: does Roger Federer’s unquestionable greatness diminish or burnish his latest title? It’s certainly not an underdog story in the vein of Buster Douglas beating Mike Tyson or Leicester City winning the Premier League. But then Douglas lost the belt in his first defence and Leicester are currently battling relegation. Surely sport’s greatest achievements belong to sport’s greatest champions, the ones who take their discipline to a place nobody thought possible. While glorious one-offs should be cherished, it is the era-defining geniuses who scale the highest peaks. On Sunday, Roger Federer might have gone higher than them all.

Read about another golden oldie in our exclusive George Foreman interview