For Brazilians, not winning the World Cup would be bad enough.
Even worse would be rival Argentina winning in Brazil where 200 million locals are expecting to celebrate.
"This would be every Brazilians worst nightmare," said Newton Cesar Santos, the Brazilian author of a 600-page history of the Brazil-Argentina rivalry — Brazil X Argentina: Stories of the Biggest Classic in World Football.
"Let anybody win, but not Argentina."
There are many intense soccer matchups: The Netherlands vs. Germany and England vs. Scotland. But none rivals Brazil vs. Argentina.
Some of Brazil's national self-esteem rests on being the world's lone soccer superpower. It's the only country to have played in every World Cup and won the most titles — five. The South Americans set the standard for flair, and 73-year-old Pele remains the game's most famous brand.
It wasn't always this way.
In the early history of soccer, it was Argentina that was the power in South America. The game arrived there before it did in Brazil. But that changed when Brazil won the 1958 World Cup, long before Argentina won its first of two — and a highly disputed victory, at that — 20 years later.
"Argentina was always much more developed than Brazil," Santos said. "They had industry. They had everything first. As a country, we admitted we were a kind of second-class country compared to Argentina."
Brazil has Pele, Argentina has Maradona and the debate about who is better never ends.
The records? It depends whose record.
The Argentine Football Association and the Brazilian Football Confederation have slightly different results. Santos has kept his own record.
"Brazil and Argentina records disagree about what is an official match or not," Santos said. "Of course, each has a record that favors its national team."
Santos calculates that from more than 99 matches, Brazil has won two more.
Santos says the first official match was Sept. 27, 1914, in Buenos Aires, which Brazil won 1-0.
Argentina fielded its first national team in 1902, according to Santos, 12 years ahead of Brazil.
"Amazingly, people have not paid that much attention to the numbers," Santos said. "Everyone knows it's very even."
Santos says there is a sector of Brazilian society hoping for Brazil to lose in the World Cup.
"They are against this government and they figure a loss could create instability, more demonstrations and force social changes," he said.
The reality of this year's World Cup is that while Argentina may have a better team and an easier draw, Brazil has the advantage of playing at home.
Brazil is placed among the favorites with Spain, Argentina and Germany, in part because it's the host nation.
Brazil's problem is the draw and, although the team led by young forward Neymar is good, few rank it as one of Brazil's greatest.
Brazil has a four-team group with Mexico, Croatia and Cameroon, but is likely to face either Spain or the Netherlands in its first game of the knockout stage. Next up could be one of three former World Cup champions — Uruguay, Italy or England.
Argentina has the world's top player in Lionel Messi and an easier draw with Bosnia Herzegovina, Iran and Nigeria, and may not face a difficult match until the quarterfinals.
Many Brazilians fear what may happen in the streets if Brazil is eliminated, particularly if it happens before the final.
"I think if Brazil loses early, or does anything but win, people will come out and express their frustration," said Marta Nagai, a Brazilian physician working in Rio. "All the issues about the big spending will be questioned."
And of course Argentines would like nothing better than to see Brazil fold. If it's in the final at the Maracana, all the better.
It happened in 1950, the last time Brazil hosted the World Cup. Brazil lost the final to Uruguay 2-1, a loss that's never forgotten in Brazil lore.
"The most beautiful thing that can happen this year is Argentina winning the World Cup in Brazil," said Celia Dominguez, who works in a dental office in Buenos Aires.
"To make it even better. Let's have Argentina win the final against Brazil with Messi scoring a penalty in the final minute."