Paraguay thrilled their fans with a slick display of attacking soccer, netting three first-half goals and completing the rout just before the final whistle when substitute Neston Ayala, who had earlier replaced Benni McCarthy’s Blackburn Rovers’ teammate Roque Santa Cruz, scored.
Santa Cruz was also on the score sheet, and the other goals came from Cristian Riveros (2) and Nelson Haedo.
In Buenos Aires, Argentina took a long time to settle due to the poor condition of the Monumental de Nunez pitch, which was full of holes and had no grass in some areas.
They only opened the scoring five minutes before half time through Aguero. Later, Riquelme scored a brace, his first from a free kick, and the second after great individual work by Messi.
Colombia notched their first goal of the current campaign when they defeated Venezuela 1-0 in Bogotá. The visitors missed numerous chances to open the scoring but Bustos punished them with a late free kick.
Five-times champions Brazil dropped to third position after being held to a 1-1 draw by Peru in Lima.
Although the home side had more ball possession and dominated the midfield, it was Brazil who broke the deadlock in the 39th minute, when Kaka scored with a brilliant shot – to illustrate just why he is favourite to become Fifa World Footballer of the Year.
Midway through the second half, Peru equalised through Juan Vargas, earning them a second point after three games.
In another match, Uruguay and Chile played to a 2-2 draw in Montevideo to leave both sides just a point behind Columbia and Brazil, with Paraguay two points ahead on seven.
Only Argentina have a 100 percent record in this competitive group.