Holders Brazil and their Group B rivals breathed life into the Copa America in two six-goal thrillers as they qualified for the quarterfinals with Venezuela and Paraguay.
Brazil won the group on goal difference from Venezuela, former whipping boys of South American soccer, with a 4-2 victory over Ecuador and will meet Paraguay in La Plata on Sunday.
Ranked 69th, Venezuela struck twice for a 3-3 draw with Paraguay in Salta that put them in a last-eight meeting with Group A winners Chile in Mendoza.
Peru, with Paraguay one of the two best third-placed teams in the event, head to Cordoba to meet Group A winners Colombia in Saturday's quarterfinals, while Argentina meet Uruguay in Santa Fe.
After a dearth of goals marred opening matches, Argentina may have sparked the tournament into life with their 3-0 victory over Costa Rica on Monday, but Brazil's display served notice the champions were beginning to gel under coach Mano Menezes.
"Today's was Brazil's best match of the tournament so far," Menezes said after two changes -- Maicon at right back and Robinho in attack -- gave his team more punch.
Young strikers Alexandre Pato and Neymar scored two goals each, winners of four of the last five tournaments, while eliminated Ecuador contributed two fine equalisers from forward Felipe Caicedo.
Typical of the traditional Brazilian virtues Menezes has sought to revive was their second goal facilitated by playmaker Paulo Henrique Ganso, who took a ball with his back to the net, turned and slotted it through for Neymar to shoot into the top corner.
Eliminated Ecuador's Colombian coach Reinaldo Rueda signed off by saying: "Given our hopes, this (tournament) was negative for Ecuador. Today we played better but it wasn't enough against effective rivals like Brazil."
Paraguay were guilty of failing to defend the two-goal lead they got four minutes from time when midfielder Cristian Riveros sent a glancing header inside the near post from a free kick from the right. Striker Nicolas Fedor pulled one back in the final minute and three minutes into added time Grenddy Perozo equalised with a diving header at a corner.