Argentina fought back to earn themselves a 1-1 draw against Bolivia, while Venezuela upset second-placed Colombia and Chile got the better of Uruguay in their 2014 World Cup Qualifiers.
South American powerhouses Argentina remain comfortably perched on the top of the group, four points clear, but it was far from a comfortable outing for Lionel Messi and co.
The Argentines had been thrashed 6-1 by Bolivia the last time the two sides met in the thin air of La Paz in the 2010 World Cup qualifiers, and the home side again produced an impressive performance.
Bolivia started the much better side with Diego Bejarano forcing a brilliant save from Sergio Romero, before Carlos Saucedo fired his free header over the bar.
The goal came in the 25th minute, when Marcel Martins brilliantly diverted a header, from an Alejandro Chumacero right-wing cross, into the back of the net.
Argentina seemed to wake up from their slumber after going a goal down, with Angel Di Maria coming close. The away side kept pressing for the equalizer and got their reward just before halftime.
Clemente Rodriguez played in a cross from the left for Ever Banega to head home.
Lionel Messi, very much in the periphery, had a perfect opportunity to give his side all three points in the final moments, but failed to find the target when one-on-one with goalkeeper Sergio Galarza.
In Puerto Ordaz, Salomon Rondon was the hero as Venezuela picked up a 1-0 win over Colombia to move up to fifth in the nine-team table. Colombia went down to third following the loss, with Ecuador, who beat Paraguay 4-1, in second.
The top four teams qualify directly for the World Cup in Brazil, with the fifth side going into a playoff.
Rondon had the only goal of the game, latching onto a through ball from Juan Arango before slotting it into the back of the net.
Colombia superstar Radamel Falcao came closest for the away side, when he struck the cross bar while looking for that elusive equalizer in the 79th minute.
Esteban Paredes and Eduardo Vargas helped Chile to a 2-0 win over Uruguay, who are now in serious danger of missing out on Brazil.
Uruguay, boasting of attacking talents of the likes of Luis Suarez and Edinson Cavani, are currently two points off fifth-placed Venezuela.
