The Argentines, with Lionel Messi proving a handful and skipper Juan Roman Riquelme rock-steady in midfield, inflicted one of Brazil's most painful defeats and intensified pressure on their under-fire national coach Carlos Dunga.
After a stalemate in the opening half, Argentina cut loose with two goals in six minutes from Atletico Madrid forward Sergio Aguero, followed by a Riquelme penalty.
Nothing is more sweeter in Argentinian football than to put one over Brazil, and their semi-final victory at the Beijing Workers' Stadium on Tuesday will rank as one of the best efforts against their South American adversaries. "I didn't imagine that we would score like this, it was such a big margin," Messi said. "We are ready for gold."
"This Argentinian team has committed themselves to each match at the Olympics in order to win the gold medal," he said. "This is what they will continue to do against Nigeria in the final. Nigeria is a really strong team."
"The reason for it all is very simple. They are the two South American teams with the most world titles and they're almost always there in the final rounds of the biggest tournaments," said Brazil coach Dunga. "It's an historical rivalry and every time they meet there's always a lot of expectation. This time was no exception of course."
"To win against Brazil is very important, not just for me, but for the Argentinean team," Riquelme said. "I saw Maradona in the VIP area and we have a wonderful relationship with him. To see him very happy makes me very happy too. Now, I hope to take the gold medal to our country like we promised."
Real Madrid midfielder Fernando Gago, another of Argentina's exciting young crop, said his team would derive plenty of confidence from the Brazilian triumph. "It was great. We played with a lot of confidence. As a team we always try to play well. We work really hard," Gago said. "For us the semi-finals and the final are the same, we treat them with equal importance, so this win is a great boost for the team."
But Mascherano said the job was yet to be completed as memories linger of the last time Argentina played Nigeria at the Olympics and lost 3-2 in the Atlanta final 12 years ago. "We haven't achieved anything yet, but beating Brazil with a result like this is wonderful," he said.