Argentina beat neighbours Uruguay 2-1 in a bruising World Cup qualifier on Saturday to end a run of six successive draws while South American group leaders Paraguay won again, 1-0 away to Colombia.
Bolivia beat Peru 3-0 in the other match and coach Erwin Sanchez said he hoped that their win could help contribute to unity in the politically-divided nation.
As the marathon 18-match campaign reached the halfway mark, Paraguay's win in Bogota kept them top with 20 points, four ahead of Argentina.
Brazil, who visit Venezuela on Sunday, and Chile, who travel to Ecuador, are a further three points behind. Uruguay's defeat kept them fifth with 12 points and Colombia stayed sixth with 10.
The top four teams qualify directly for South Africa and the fifth play off against a team from the CONCACAF region.
Argentina coach Alfio Basile, who likes his team to play with verve and style, admitted that all he wanted on Saturday was a win, whether it was pretty or not.
"A result was fundamental today and we got it," he said.
Argentina forward Lionel Messi headed in after six minutes from a cross provided by Juan Roman Riquelme, whose place had been under threat after a run of lacklustre displays.
Sergio Aguero added another seven minutes later and Martin Demichelis had another goal disallowed for offside before the half hour in Buenos Aires.
The game appeared to be a stroll for Argentina but turned into a battle after Diego Lugano pulled one back five minutes before halftime.
The second half produced the sort of ferocious tackling and scuffles often associated with the River Plate derby.
"The referee was a disaster," growled Basile. "His permissiveness allowed Uruguay to interrupt the spectacle.
"We did what could in a game where the opposition kicks the hell out of you."
Paraguay handed Colombia's new coach Eduardo Lara a losing start when Salvador Cabanas caught goalkeeper Agustin Julio off his guard and scored with a swerving 30-metre shot from near the touchline in the ninth minute.
Colombia, who have scored only four goals in nine games, slumped to a third straight defeat in the group.
Bolivia forward Joaquin Botero scored twice in the first 20 minutes against Peru to become his country's leading international scorer with 17 goals, overtaking Victor Ugarte's record from the 1960s.
Ronald Garcia added a third in the 81st minute as Bolivia (eight points) moved off the bottom and were replaced by Peru.
"This win is dedicated to all of Bolivia, which needs this type of happiness," said coach Sanchez.
"I hope things calm down a little, that we might have contributed a grain of sand towards genuine dialogue, that there can be peace in our country and that we can live in harmony."
Bolivia is mired in a long-running conflict between leftist President Evo Morales and rightist governors from the country's lowland regions.