Chile produced an inspired performance to beat disjointed Argentina 1-0 win their World Cup qualifier on Wednesday.
Fabian Orellana finished off a sweeping move in the 36th minute to give Chile, led by former Argentina coach Marcelo Bielsa, their first win over their neighbours since 1973 and the first in a World Cup qualifier.
The result left the two sides level on 16 points from 10 games in the 10-team South America and piled the pressure on Argentina coach Alfio Basile.
It was his team's first defeat this year and possibly their worst performance of his two years in charge.
The first half was halted for seven minutes after a clash of heads between Argentina defender Nicolas Burdisso and Chile forward Mark Gonzalez, who were both carried off.
Argentina, missing the suspended Juan Roman Riquelme, struggled to get into their stride without the mercurial playmaker who had been ever-present in the qualifiers.
Chile, with an average age of just over 24, looked lively as Jean Beausejour had a dipping long-range effort tipped over by Juan Pablo Carrizo, Pablo Contreras scraped the crossbar with a header and Matias Fernandez curled a free kick narrowly wide.
They went ahead with a superbly-built goal as Beausejour found Gary Medel on the right and he played a one-two with Carlos Carmona before pulling a low ball into the penalty area which was swept in by Orellana.
Argentina's Lionel Messi nearly broke through after swapping passes with Sergio Aguero but was eventually crowded out.
Basile replaced striker Diego Milito with uncapped Gonzalo Bergessio at halftime but Chile continued to pour forward.
Humberto Suazo toe-poked narrowly wide from the edge of the area before Hugo Droguett had a shot headed off the line by replacement defender Daniel Diaz.
Argentina's best efforts came in the last 10 minutes when Messi burst through the defence and saw his chipped shot headed off the line and Martin Dimechelis headed narrowly wide.