The man they call El Oso (“The Bear”) is not his usual hairy self, having shaved off his trademark beard to honour a promise he made on the outcome of the Copa Libertadores final. He has also pledged to get a tattoo, but is leaving that until he gets back home.

"After winning the Libertadores final, I’m looking at this Club World Cup like a reward. I want to win it but it’s a gift for me to be here,” Lucas Pratto said in an exclusive interview with FIFA.com.

"It’s the first Libertadores I’ve ever been lucky enough to win and this is the first Club World Cup I’ve ever been fortunate enough to play in,” he added. “It’s something I’ve been dreaming about since I was a boy. When you grow up in South America you dream about winning the Libertadores and playing for your country. Well, I’ve had the good fortune to fulfil my two dreams, and I hope to cap it all by winning the Club World Cup too.”

A Boca Juniors youth product, Pratto has just fulfilled his childhood dreams with River, scoring some vital goals as they secured their fourth Libertadores crown. His five-goal haul made him his club’s leading scorer in the competition and included two unforgettable strikes.

“The two goals against Boca were special, against our age-old rivals, in the two legs of the final, first away and then at the Bernabeu,” he smiled. “And I couldn’t choose one above the other; they were both very important.” Singling out some of his team-mates for praise, he added: “The thing is, though, we’ve got Juan Fernando [Quintero], Pity [Gonzalo Martinez], and Nacho Fernandez. When you’ve got people them behind you, it makes it much easier for the front men.”

River improved as the Libertadores went on, and their epic final win has given them the perfect boost as they head into the Club World Cup, a tournament of great significance for South American clubs.

“It’s very special for us because we have the chance, if we manage to reach the final, to take on the champions of Europe, who usually get there. Taking on clubs of that calibre always brings out the best in South American sides, especially Argentinian ones; we always want to beat the strongest to show that we are as good as them.”

As well as their positive frame of mind and the motivation Pratto points to, River are also in excellent form.

Explaining their attributes, the striker said: “We’re very strong, and we really do have a winning mindset and bags of character. We fell behind against the toughest rivals, like the defending champions [Gremio], both home and away, and we managed to turn it around. And we also came from behind in the two legs of the final against Boca. We’ve got players with a lot of skill, but we’re also mentally strong and that’s because we’ve got a great squad.”

River also have Marcelo Gallardo, of course: “He sets the strategy and the tactics, but he also gives us leadership and a very clear message, which makes it really easy for us to then go and do what he asks of us on the pitch. He also gets the history of the club across to us, the sense of belonging to this club.”

With all those assets on their side, Los Millonarios are determined to make up for their defeat in the 2015 final, when a combination of Lionel Messi’s magic and Luis Suarez’s goals consigned them to defeat against Luis Enrique’s Barcelona.

“Having beaten our eternal rivals in a historic final, I think we have the mindset and the experience to go out and fight for this Club World Cup.”