On June 26, 2011, Barcelona's players and staff were still basking in the triumph of a third Champions League title in six years. Lionel Messi had led the way with 12 goals in the tournament, and at the end of the year Santos would be blown away to ensure yet another trophy for the brilliant Catalans.
Their opponents on Sunday, however, were going through the most acute crisis in their 100 years of existence. Mariano Pavone's missed penalty in front of an enraged Monumental Stadium had only rubbed salt into the wounds of a 3-1 aggregate defeat to Belgrano which condemned River Plate to their first-ever relegation.
Most of the River squad, including a teenage Erik Lamela who had fought harder than anyone to ensure their survival, sat disconsolate, weeping on the green expanses of the ground which had given the club so much joy over the decades. Their anguish was shared by the vast majority of fans, left heartbroken in the terraces. A small minority decided to leave their own mark on that black date, ripping out seats, rioting and setting fire to sections of the stands while vandalism and looting was reported outside.
An acrid pall descended on the site of Argentina's 1978 World Cup victory, the setting for dozens of titles and cup successes, and when the smoke cleared the reality set in. Not only had River gone down, but the club had been taken to the brink of oblivion thanks to years of mismanagement and corruption, first under Jose Maria Aguilar and then Daniel Passarella in the presidency. Multi-million dollar debts and a swollen, under-achieving squad were the legacy left by that disastrous campaign, and the mere suggestion that just over four years later the team would be fighting for the right to call themselves world champions would have sounded ridiculous, cruel even.
But the wonderful thing about sport is that the opportunity to bounce back is always present. River took their chances, and there is no more fitting opponent for Barcelona's all-stars this Sunday than a team that, through hard work and no little humility, have clawed their way back to the big-time.
It was Matias Almeyda who started the renaissance. The ex-River midfielder picked himself straight up from the turf on that fateful day, hung up his boots and moved onto the bench as coach. Young stars such as Lamela and Lucas Ocampos emigrated to European football, easing the accounts with hefty transfer fees; but in the other direction Alejandro 'Chori' Dominguez and Fernando Cavenaghi arrived, desperate to restore their boyhood idols to their rightful place in Primera.
River suffered a long, hard campaign in the Nacional B. Fellow fallen giants Rosario Central were also keen to put the second-tier behind them, and out of Cordoba appeared a 17-year-old wizard by the name of Paulo Dybala who took the division by storm. But the overwhelming support from fans, who followed the side over thousands of kilometres from Patagonia to Jujuy, saw them through, as did a little help from David Trezeguet who landed in January to fulfil his childhood dream and pull on the famous white shirt with the red stripe. Promotion was eventually sealed on the last day of the season, and the club have never looked back since.
Almeyda was rather rudely discarded after the 2012 Inicial season, and a club icon was welcomed back. Ramon Diaz had led the club to glory in the 1990s and he would do so again, in his own idiosyncratic way. Like a South American Jose Mourinho he took all the flak, enraging a pressure-cooker Bombonera with his "I wasn't relegated" gesture as he resumed hostilities with old foe Boca Juniors. His team did not quite represent the "win, please, thrash" ethos of the club but few cared as Ramiro Funes Mori's famous Superclasico header put the team on course for the title in 2014.
Diaz stepped down, and another club favourite assumed command. Marcelo Gallardo's arrival at the Monumental was as significant as the day Pep Guardiola first took control at the Camp Nou, as his team played a hard-pressing, passing style which was a breath of fresh air in the stagnant Primera Division. The Copa Sudamericana followed, and in the next year Gallardo was brandishing South America's biggest prize, ending River's 19-year Libertadores drought.
There is no single man responsible for River's journey from a football infierno to the Mt. Olympus of Japan and the Club World Cup. Almeyda and Diaz both left the foundations for Gallardo to continue building, a continuity seldom seen in Argentine football where six months is seen as almost long-term thinking. On the pitch, academy products such as Funes Mori, Matias Kranevitter and Eder Alvarez Balanta have been supplemented by intelligent purchases, from Marcelo Barovero between the posts to relentless Urguayan midfielder Carlos Sanchez and the controversial Teofilo Gutierrez, now at Sporting, up front.
In the boardroom, meanwhile, Rodolfo D'Onofrio deserves great credit for turning round the awful situation left by Passarella. His presidency has typified the new River: softly-spoken, humble, but hugely effective and efficient.
Merely making the final in Japan is a spectacular achievement for the Millonarios. The Club World Cup has dominated thoughts in the club ever since Tigres were vanquished to lift the Libertadores, and the presence of 18,000 or more River fans on the other side of the globe merely emphasises just how much this means for everyone involved. Those same supporters tasted the worst possible feeling in football less than five years ago, and lived to tell the tale - now Barcelona and Messi beckon, and who's to say that the fairytale does not have one more happy ending left?