Chile came from a goal down to beat an under-strength Mexico 2-1 at the Copa America, while World Cup semi-finalists Uruguay also had to fight back to earn a 1-1 draw with Peru.
Uruguay's draw yesterday means all three seeded sides at the tournament have failed to win their opening matches. Hosts Argentina were held 1-1 by Bolivia, while Brazil were held 0-0 by Venezuela.
All 12 teams in the competition have now played a game, with four of the six matches ending in draws. Colombia and Chile are the only sides to have won, both by a single goal.
Uruguay, with Diego Forlan and Luis Suarez in attack, had been expected to beat a Peru side who finished bottom of the South American qualifying group for the 2010 World Cup.
However, it was the Peruvians who took the lead in the 24th minute through striker Paolo Guerrero of the Group C clash against the run of play.
Uruguay kept plugging away and in first-half injury time, Suarez equalised.
Hours later in the same stadium, Chile also fell behind against the run of play, with Mexico's Nestor Araujo looping a header over goalkeeper Claudio Bravo just before halftime.
But the Chileans equalised in the 67th minute through second half substitute Esteban Paredes, who stole in at the back post to thrash the ball into the net from close range following a scramble in the box.
Six minutes later Arturo Vidal grabbed Chile's winner with a towering header from a corner, which rocketed into the top corner of the Mexican net.