Stanislas Wawrinka’s backhand down the line was leaving a searing streak in memory. But his quarter-final match at the US Open in September is mainly remembered for the applause his fading opponent Juan Martin del Potro received. In the closing minutes of the match, with the clock ticking past 1 in the morning, the Arthur Ashe stadium erupted in a cheer of “Delpo, Delpo".

The Argentine’s spirit by now had been sapped in a humid New York night, but the crowd wasn’t quite ready to let him go. Overcome by emotion, Del Potro, then trying to get into position to return serve, paced the baseline and shed a few grateful tears for the love cascading down from the stands. Life had sometimes been cruel, his wrists too fragile to sculpt a consistently glorious career (he’s had three surgeries on his left wrist, and one on his right since winning the 2009 US Open).

But this, right here, was realization. People cared, he mattered to the game. He was not part of the “Big Four" and the last—the only—time he won a Grand Slam was in 2009 at the US Open. But his power game, accented with that slapping forehand, and his affability had long reeled in supporters across the globe.

“Something difficult to describe with words," Del Potro said after his 6-7, 6-4, 3-6, 2-6 loss to Wawrinka. “I can lose the match, but I will never forget this. You know, it’s bigger than winning any match. I’m so proud to get that from the crowd, because I have been doing a big effort to play tennis again. They made me so happy tonight, and I don’t mind the score."

The “Tower of Tandil", who this season sought to come back from his third wrist surgery, has made rapid strides on the rankings chart and come Friday, will be tasked with leading Argentina to their first Davis Cup title.

Argentina will take on hosts Croatia in the final in Zagreb. While 2014 US Open champion Marin Čilić will be Croatia’s leading player in the tie, Del Potro, five days older than Čilić, will hold sway for Argentina.

Though Argentina have produced some greats in the game, they have been unable to get their hands on the team trophy in their 62 years of participation. They hold the dubious record of having made the most finals—four (1981, 2006, 2008, 2011)—without having won the Davis Cup, which parades as the world cup of tennis. But with Del Potro coming to form in the last few months, they are hoping to get fifth time lucky.

The 28-year-old had started the year at a ranking of 590 but will enter the Davis Cup final weekend ranked 38 in the world. Though he took time to ease back into the din of a super competitive men’s tour, he has showed just how devastatingly beautiful his game can be.

He defeated Novak Djokovic in the first round, and Rafael Nadal in the semi-final, to finish with a silver medal at the Rio Olympics after losing to Andy Murray. Del Potro then won a nerve-wracking first singles rubber against Murray to land a decisive blow on Great Britain and their morale in the Davis Cup semi-finals in September. He finally won a title this season when he claimed the Stockholm Open in October. At the recent ATP awards, he was named the “Comeback Player of the Year".

While Del Potro goes into the tie well-rested—he last played in Basel in the ATP tournament that ran from 24-30 October—Čilić, will come in hot from the ATP World Tour Finals. The Croat, who stands at an identical 6ft, 6 inches, is ranked 6 in the world and has been one of the most consistent performers this season. Čilić and his monstrous serve could potentially thwart Argentina’s ambitions.

The 28-year-old is bidding to equal Ivan Ljubičić’s record for the most singles wins for Croatia and has been crucial in Croatia getting as far as the finals. He was called in to play all three days of the quarter-final tie against the US and the semi-finals against France, and Čilić delivered—losing only one of those six matches, a tough five-setter against America’s Jack Sock.

While the clash of the two big men—Čilić and Del Potro—will go a long way in deciding which way the tie swings, the bench strength will eventually come into play. The hosts may have a slight advantage here. They have recalled veteran ace-machine Ivo Karlović from international retirement as a foil for an injured Borna Ćorić. In Ivan Dodig, they have an experienced doubles campaigner.

Argentina, meanwhile, will rely more on the spunk of their young brigade than balance and experience. Guido Pella and Federico Delbonis, the second singles players, have been good enough to get them over the line so far this campaign. Facing the fierce Croats, on their own courts, will be a tough prospect.

But it gives Del Potro, who will undoubtedly be the neutrals’ favourite, another chance to cement his comeback. It is not until he returned to the courts, that the tennis world realized the joy he brings to the game. A Davis Cup win could provide a perfect season-ending for his story.

Teams (world ranking)

Argentina: Juan Martin del Potro (38), Federico Delbonis (41), Guido Pella (72), Leonardo Mayer (doubles: 122); non-playing captain: Daniel Orsanic

Croatia: Marin Čilić (6), Ivo Karlović (20), Borna Ćorić (48), Ivan Dodig (doubles: 13); non-playing captain: Željko Krajan