Nadal and Federer at the Australian Open final.

Every possible end to this year’s Australian Open would’ve made a story for the ages. Don’t believe me? Go ahead and pick one. Venus Williams at thirty-six, winning her first major in nine years. Serena Williams at thirty-five, returning to top form, winning her record twenty-third major title and reclaiming the number-one ranking. Roger Federer at thirty-five, winning an improbable eighteenth major title after a sixth-month hiatus, and against his one true rival. Rafa Nadal, at thirty—having seemed, in recent seasons, gnawed on by Father Time, with all the guilty, wide-eyed ravenousness of Goya’s Saturn Devouring His Son—unexpectedly capturing his fifteenth major title and making his strongest claim yet to being the greatest player the men’s tour has ever seen.

Every possible outcome would’ve hit some sweet spot. The Australian Open was a chance to cheer the younger, all-conquering versions of Venus, Roger, Serena, and Rafa—an opportunity to remember how quickly these moments we have to define ourselves can pass us by, and how thin the margins can be. Watching tennis like this appeals to that part of you that flutters and pinwheels: the nostalgia of the cynic, the romance buried in the hard-hearted. It felt like Pluto was the ninth planet again, singing sweeter in the music of the spheres than ever before.

Tennis is a game of undulating rhythms that exist in four concentric circles—the rhythm of a point, the rhythm of a service game, the rhythm of a return game, the rhythm of a set. They’re interrelated, but they don’t necessarily touch. Like an idea of order.

For example, serving with advantage in the fifth set, Nadal looked poised to pestle Federer in this, their thirty-fourth match. (He’d already won twenty-three of the others.) True, no player has won as often as Federer, but no player has made him suffer like Nadal has. The two first played in 2004, when, in Miami, a seventeen-year-old Nadal sent ripples through the tennis world by defeating the top-ranked Federer, then twenty-three, in straight sets. Since then, they have faced each other on hard courts and clay courts, quick courts and slow courts, half-clay and half-grass courts, Dubai courts and Cincinnati courts—for better and for worse, in sickness and in health.

Nadal’s advantages have been largely physiological. His thumping, left-handed, topspin forehand has spent the better part of a decade grinding down Federer’s backhand—a backhand that is, crucially, one-handed. The deep, high-bouncing ball is this backhand’s structural flaw, like that blind spot in a car’s rearview mirror. It’s extremely difficult to generate pace with such a backhand, especially while Nadal, like Navratilova and McEnroe before him, has made an art of his left-handedness. His game is a mosaic of stroke patterns designed to advantage what in Latin, and still in Spanish, would be known as his sinister side. If Federer’s elegant, artisanal backhand has been the cobra of the ATP Tour, Nadal’s forehand has been the mongoose.

But Federer brought a surprise with him to this final: he’d altered his backhand. Suddenly, he was hitting it flatter. Much flatter. You could see the difference in the shot off the racquet, and in his follow-through. It was curt—the high curlicue finish of the racquet with the twist of the wrist was gone. Now he swung the backhand more like someone opening a stuck door.

Ironically, Federer’s attempts to save himself in a point by using the topspin and slice often led to his demise in these matchups. Nadal knew it. Federer knew it, too, but he seemed unable to adjust. The strength of his one-handed backhand is in its flexibility. It’s an easier stroke through which to master and disguise variations of spin. And unless you’re Nicolás Almagro, Richard Gasquet, or Stan Wawrinka, there’s not much you can do off the backhand wing with a one-handed when you’re pushed to the back of the court but slice the ball back. So Federer, possibly taking cues from Grigor Dimitrov’s electric semifinal performance against Nadal, decided almost without fail to swing hard and swing flat, without fear of Rafa’s forehand. It bore fruit for Federer in the first and third sets, but the second and fourth were near mirror images of each other, with Federer’s own forehand—widely considered the greatest shot in the history of tennis—letting him down repeatedly.

And so there they were, the one secret between the two of them now out in the open. Nadal had had four sets to learn Federer’s backhand adjustment, and the match seemed to have stabilized. Nadal was one point from 4–2, with a vise grip on the match—he leaned forward at the baseline, fidgeted with one shoulder and then the other, touched one side of his nose and then the other, and then the other again; pushed aside his hair, picked at his shorts from the back, all prologue to the motion of his serve.

The point total at this moment of the match: Federer, 131; Nadal, 131.

As Nadal, mid serve, stared up at the ball hanging tamely in the air above him, he was never closer to winning the match. Then he tried to surprise Federer with a body serve, and Federer, on reflex, blocked the ball, and it tumbled crosscourt, deep into the corner it came from. Federer, completely on the defensive now, repositioned himself at the center of the baseline. All he could do now was wait. Nadal went for the wide shot he’d passed up on the serve. Soon a lane for a short crosscourt winner opened up, a shot tailor-made for Nadal’s lefty topspin forehand. Nadal went for it and it clipped the tape on the top of the net. But the topspin didn’t allow the unforced error to die a quick death, no—it popped and remaindered down to a spot on the court, falling, in the end, far enough to be out without question, even at first glance.

The next point was a rapid-fire five-shot slugfest that Federer ended emphatically with a flat backhand crosscourt winner. The break comes shortly after, Nadal spraying an inside-out forehand from the deuce side wide at the end of another hard exchange of ground strokes. Nadal is broken: three-all in the fifth now. Nadal never won another game in the match; he claimed only eight more points. Sure, there was the quality and emphatic drama of the twenty-six-shot rally two games later with Federer surging at 4–3. But it was Nadal’s unforced error—when everything was balanced seemingly on the width of an atom—that changed everything. They say baseball is a game of inches, but a debate that could have lasted a lifetime—who’s the greatest male tennis player you’ve ever seen?—was ended by a quarter-centimeter of braided net cord as the world turned.

Rowan Ricardo Phillips is the author of The Ground and Heaven. He is currently writing a book about tennis, The Circuit, which will be published in 2018.