Argentina, helped by a majestic Juan Roman Riquelme performance, maintained their perfect record in the World Cup qualifiers on Saturday while Ecuador coach Luis Fernando Suarez quit after a 5-1 loss to Paraguay.
Riquelme scored two second half goals, including an exquisite free kick, in a 3-0 win over Bolivia which left Argentina with nine points from three games in the South American group.
Ecuador's chances of a third successive appearance at the finals already look slim after they followed up last month's 5-0 loss in Brazil with another heavy defeat.
The result, which left them pointless at the bottom of the 10-team group, prompted Suarez to resign and become the first coaching victim of the competition.
In Saturday's other game, Colombia escaped their third successive scoreless draw when Ruben Dario Bustos scored from a 30-metre free kick to give them a 1-0 win over Venezuela.
The third round of matches in the two-year campaign will be completed on Sunday when Peru host Brazil and Uruguay entertain Chile.
Argentina, who will be top of the group regardless of results on Sunday struggled to break down their stubborn opponents for 40 minutes, before the two-times world champions went ahead when Sergio Aguero, 19, headed his first international goal.
That opened the way for another Riquelme master class.
The playmaker signalled his intentions with a 25-metre free kick which was tipped away by Carlos Arias in the 51st minute.
Six minutes later, Riquelme took another free kick from a similar position and this time left Arias helpless as he found the top left-hand corner from 30 metres.
He followed that up with a stylish sidefooted goal from Lionel Messi's run in the 74th minute.
Ecuador arrived in Paraguay amid reports of internal squabbling after experienced defenders Ulises de la Cruz and Ivan Hurtado were left out of the squad.
They were quickly in trouble as Nelson Haedo Valdez and Cristian Riveros scored from corners to put Paraguay 2-0 ahead within half an hour.
Roque Santa Cruz added a superb third early in the second half and, although Ivan Kaviedes pulled one back, Nelson Ayala and Riveros scored twice more for the rampant hosts, who have seven points.
"My decision has been taken exclusively for the good of the Ecuador team, which will surely have a better campaign without me," said Suarez, who led his side to the last 16 at the World Cup in Germany.
Colombia scored their first goal of the campaign when Ruben Dario Bustos fired in a 30-metre free kick with eight minutes remaining to sink Venezuela.
The goal unleashed frenzied celebrations at El Campin in Bogota where the crowd had been getting increasingly exasperated as Colombia pressed forward but struggled to find a way past Leonardo Morales.
Colombia, who last qualified for the finals in 1998, have five points while Venezuela, who have never played at a World Cup, have three.
Paraguay 5 Ecuador 1
Colombia 1 Venezuela 0
Argentina 3 Bolivia 0