Juan Martin del Potro and Novak Djokovic were sitting together on the doorstep of greatness nearly a decade ago, awaiting what felt like imminent admission.

Each man had one Grand Slam title to his name, Del Potro’s from the 2009 US Open – where, at 20 years old, he’d beaten Rafael Nadal and Roger Federer in the semis and finals. Djokovic and Del Potro finished the year ranked third and fifth in the world, respectively, the two youngest players inside the top 10.

Their paths diverged significantly after that, but on Sunday, they met in the US Open final, both having returned to the top of the sport after setbacks of varying severity. As brilliantly as the revitalized Del Potro played at points, Djokovic has developed a gear that the Argentine cannot match. For the victor, now tied with Pete Sampras for third all time with 14 major titles, it completed a once unthinkable in-season turnaround. For Del Potro, playing just the second Grand Slam final of his career, a grueling journey ended in disappointment at the precipice of glory – a destination he can no longer take for granted that he’ll reach.

Sometimes, watching Djokovic return serves recalls the theory of retrocausality. He can be so quick to the ball, so certain of where it’s going to land and how it’s going to bounce, so aware of how to square it up and block it back so that it lands just inside the opposite baseline, that he appears to be operating on an alternate, atemporal plane. For most of Sunday’s match, Djokovic’s first move off the mark seemed to determine where Del Potro’s serve would end up, rather than the other way around.

Djokovic’s returns neutralized one of the biggest weapons in the sport. He reset point after point by knocking back serves that routinely clocked in over 130 mph, and sending many of them back – with interest – right at Del Potro’s feet. The Argentine got precious few short put-away balls in response; nothing came easy. Once the points got bumped back to neutral, Djokovic dragged him around the court, attacking his feet, his legs, and his lungs. On a slower-than-usual hardcourt, even the most nuclear Del Potro forehands struggled to puncture Djokovic’s defensive barricade.

“I was playing almost at the limit all the time, looking for winners with my forehands, backhands,” Del Potro said. “And I couldn’t make it because Novak was there every time.”

Djokovic’s own forehand was brilliant. He’d go inside-out to slowly nudge Del Potro further and further away from his vastly preferred wing before pulling the trigger cross-court and making him defend to his forehand side. Del Potro popped off a few monstrous on-the-run forehands, as he does, but he rarely had the time or space to set up for the shot, and couldn’t maintain a rhythm. Djokovic kept attacking to that side, kept taking Del Potro’s time away. By the end of the match, the most powerful groundstroke in the game had begun to break down.

The outcome was settled when Djokovic, already up a set, wrested away the grinding, 95-minute second, which included a 20-minute, 23-point service hold in the eighth game. Del Potro had come back from a break down earlier in the set, had had four break points in that eighth game, and jumped out to a 3-1 lead in the tiebreaker. But, at the peak of his powers, Djokovic’s mastery of big-point risk management and controlled aggression makes him virtually impossible to close out. He seems to win those long, taut, all-important sets every time.

The pro-Delpo crowd, with its strong Argentinian contingent, did its utmost to prop up the Tower of Tandil, but Djokovic managed to turn his opponent’s support into his own fuel.

“This might sound funny, but my nickname is Nole. When they shout ‘Ole, ole, ole, ole,’ that’s what I hear,” Djokovic said after the match, referring to the most popular chant from Del Potro’s supporters. “I actually make myself hear that, to be honest. No word of a lie.”

And so, Djokovic won his third US Open title in straight sets, a staggering outcome considering his catastrophic first half of 2018. He struggled with an elbow injury and underwent surgery. His movement looked hampered, he seemed to suffer from a lack of mental acuity, and he displayed little of the relentlessness that has otherwise been his signature. He lost six of his first 12 matches, including four to players ranked outside the top 40. His French Open quarterfinal flameout against 72nd-ranked Marco Cecchinato marked two years since he’d last won a major. It was confounding, bleak, decline-auguring stuff. Now, he’ll finish the year as the only player to win two Slams. In the run-up to the US Open, he collected his elusive championship in Cincinnati to become the first player to win all nine Masters events. He has the inside track in the race to be crowned year-end No. 1. All in a summer’s work.

“My life has turned upside down in the last couple years with so many different things, changes that happened,” he said. “Becoming a father twice, being away from the tour six months, getting surgery, all these different things. If you told me in February this year when I got the surgery that I’ll win Wimbledon, US Open, and Cincinnati, would be hard to believe.”

Lest we forget the spiritual champion of the tournament, let’s hear it one more time for Del Potro. In 2009, after a 20-year-old Del Potro beat Nadal and Federer back-to-back to win his first Slam, imagine thinking that it would take him nine years just to get back to the final of one. He had as many major titles as Djokovic, and one more than Andy Murray. He finished that year as the youngest player ranked inside the top 10. There wasn’t supposed to be a Big Four – not without him.

He underwent four wrist surgeries (three on his left wrist) after his precocious breakthrough, however, and I have a distinct, haunted memory of watching one of his first matches back from the third operation. In March 2015, he played Vasek Pospisil in the first round of the Miami Open – not a daunting opponent, but one who hits hard enough to make life difficult for someone who doesn’t trust his body. And Del Potro didn’t trust his wrist at all. His two-handed backhand was virtually non-existent, and he used the slice almost exclusively. He was tentative, still cracking big forehands but mostly just hitting them down the middle of the court. His movement was robotic where it had once been fluid. He lost in straight sets, hitting just two winners all match.

He shut things down immediately after that, underwent another surgery on his left wrist, and spent another 11 months away from the tour, during which he seriously considered retirement. He was tired of the ups and downs, the long recoveries, the struggles to regain his fitness and re-establish his ranking, the steel-toed boot of circumstance kicking him back down the mountain any time he appeared ready to crest the summit once more. Between 2014 and 2016, he sat out nine Grand Slams in a row.

But he soldiered on and worked his way back, mentally and physically. He slowly rebuilt his backhand while continuing to mash 100-mph forehands on the regular. He beat Djokovic and Nadal on his way to a silver medal at the Rio Olympics. He beat Federer in Flushing Meadows last year to reach his first Slam semi since 2013. He beat Federer again at Indian Wells this year to win his first-ever Masters title. He achieved a career-high ranking of No. 3. And after losing to Nadal at three of the last four Slams, he overcame him (hobbled as Nadal may have been) to reach the US Open final.

Alas, he encountered peak Djokovic there, and that guy doesn’t lose, to anyone. Still, watching Del Potro move around and hit without limits, watching him do damage with powerful topspin backhands down the line, felt almost surreal. That 2015 match was never far from my mind; at the time, I’d assumed that he was finished competing for meaningful trophies.

“I’ve been crying until now,” Del Potro told reporters at his post-match presser.

Now that he’s healthy and back to playing some of his best tennis, it would be easy to say that there will be other opportunities. But Del Potro understands how quickly and unexpectedly fortunes in this game can change.

“I don’t know when will be my last tournament in this career, but I’m excited to keep surprising myself doing things like this,” he said. “I’m very motivated to keep trying to win these titles.”

Hopefully, he won’t have to wait nine years for his next chance.

(Photos courtesy: Getty Images)