BRASILIA - Salivating over the prospect of a potential World Cup final against their hosts, thousands of Argentina fans have poured into Brazil's capital Brasilia for Saturday's quarter-final against Belgium.
To cope with the football 'invasion' by Brazil's "brother" nation and major rival, authorities have fitted out Brasilia's parks with showers and loos, drinking water supplies and a giant screen.
The two South American giants still have work to do before they can dream of a first ever final meeting.
Brazil, shorn of their star player Neymar, have the small matter of a semi-final against Germany and Argentina need to get past Belgium, then either the Netherlands or Costa Rica.
But the very idea they might meet on July 13 in Rio's Maracana is already stoking passions.
"Argentina will get to the final and win the Cup," shouted Argentinian student Federico Brandolini, 23 - who is staying with his 21-year-old Brazilian friend Moroni Chaves.
Chaves has a slightly different view.
"They think they're on their way to the final but Argentina won't get past Belgium and it will stop there for them.
"Brazil will be champions," he insisted, even with the loss of Neymar through injury and skipper Thiago Silva also due to miss the last four clash because of suspension.
"Argentina and Brasil consider each other as the cream of South American football and that fuels huge sporting rivalry," says Raul Bernal-Mezza, professor of international relations at Buenos Aires University, who has spent years in Brazil.
"All Argentinians want Brazil to lose and all Brazilians want Argentina to lose." Both countries lay constant claim to the 'best player of all time' epithet - Pele in the Brazilian corner with Diego Maradona for Argentina.
Then there is the current rivalry between Lionel Messi and Neymar - clubmates at Barcelona.
For Argentinian fans, "Messi is going to bag us the Cup; Maradona is greater than Pele," has been their constant refrain during this year's competition.
For the Belgian game, the Brasilia authorities have laid on a huge campsite in an exhibition park to the north of the city with space for the tens of thousands of fans who have made the trip.
The two giants of South American football - seven world titles between them to date - goes back to a first meeting 100 years ago, a friendly Argentina won on September 20, 1914.
A week later, Brazil lifted the Copa Roca in the first official match between the two.
Argentina won their last World Cup finals meeting on the way to losing the 1990 final to Germany.
But their record, comprising wins in 1978 and 1986, pales alongside Brazil's who triumphed in 1958, 1962, 1970, 1994 and 2002.
"For us, one way of getting one over Brazil would be to win this Cup in their back yard," says Nicolas Padilha, 29, who has been following the 'albi-celeste' across Brazil since the event began.
Argentina have had their massed ranks behind them for all of their games so far, with some 90,000 present for matches in Rio de Janeiro and Porto Alegre and 70,000 in Sao Paulo.
In Brasilia, anything between around the 40,000 their embassy expects and the police forecast of 60,000 are set to cheer them on.
Brazil's authorities have made special security arrangements and over 3,000 police will be on hand.
Airports are on maximum surveillance in order to prevent Argentina's 'barra bravas' or hooligan element making it to the game.
"The Brazilians have opened their doors to us and have helped us throughout with accommodation," said one fan, Elias Sarouf as he prepared a barbecue in front of a somewhat beaten up Mercedes van which is doubling as a place to rest for the night.
"The rivalry is on the pitch. The Argentinians are very nice and we Brazilians love going to Buenos Aires and are well received over there," explained a Brasilia teacher called Helena.
Brazilians and Argentinians alike also share the same World Cup dream: "We all want to go to the Maracana" on June 13 - harbouring hopes of beating each other.