Chile supporters made the most of Rio -- indeed, a ticket-less band of them literally invaded the Maracana stadium before the game, charging in through the press entrance in a bid to watch their team. On the morning of the game in the streets of Copacabana, when groups of Chileans ran into each other they would clap and shout out that they were going to send Spain back home -- and they seemed to believe it.
Such is the faith in the side led by electric little coach Jorge Sampaoli, who seems to run on batteries as he paces up and down the touchline.
True -- Spain are clearly not what they were. A decline was apparent in the course of last year's Confederations Cup. In the first half of their opening match against Uruguay last summer they were simply dazzling, full of midfield triangles, each one opening up possibilities for further triangles as the opposition were left chasing shadows. But as the tournament wore on, the speed and quality of the passing declined -- a process which has clearly continued. Chile keeper Claudio Bravo made some good saves, there was the occasional moment of genius from Andres Iniesta, but there was also a lack of that old fluidity. The ball was never fizzing about as it did when Spain ruled the world.
But they still had to be beaten. It happened in the first game of the last World Cup, when Switzerland parked the bus and snuck away with a 1-0 win. The 2010 Swiss, though, were so limited they did not even make it out of the group. Chile are a different matter. They never looked to park the bus. Their aim was always to drive it straight through the heart of the Spanish defence.
Chile are that most dangerous of opponents -- a team armed with an idea, an identity. This had always been lacking from the country's football in the past. The problem was solved when Argentine maestro Marcelo Bielsa took over the national team in 2007.
It was the perfect moment to step in, too. A talented generation of players had just come third in the 2007 World Under-20 Cup. It was also a perfect place. The lack of a defined identity made it easier for Bielsa to implant his philosophy, which had always met with resistance in his native Argentina. Bielsa wanted to attack, playing high tempo, pressing football in the opponent's half of the field, throwing forward both full-backs at the same time in a constant quest to set up two-against-one situations down the flanks.
Chile's youngsters took to it with ease. It suited a country that normally produces lots of tricky dribblers; defending high also eased the pressure on a back line frequently short of height.
Chile were the neutral's favourites in South Africa 2010, winning over hearts and minds with their bold approach before falling to Brazil in the second round. Now they aspire to something better. The same group of players, youngsters four years ago, are now approaching their footballing prime. And in coach Sampaoli they have a self-confessed Bielsa disciple, consolidating a philosophy that has now become part of the DNA.
It was not only their fans, then, who had faith that Chile could see off the Spaniards. The players, too, are committed to what they are doing and confident in their own capacity to take on any team, anywhere and impose themselves on the game -- which is exactly what they did in the Maracana on Wednesday.
Chile's 2-0 win does indeed send Spain home early, and brings a wonderful era of Spanish domination to a close. How appropriate that the knock-out blow should come from a team who are not characterised by caution, but instead by one which lives and breathes boldness.
Tim Vickery is an English journalist who has been based in Brazil for the past 20 years. He is the South American football correspondent for the BBC Sport.