Holders Estudiantes beat San Luis of Mexico 3-1 to qualify 4-1 on aggregate and Cruzeiro, last year's runners-up, eased through with a 3-0 away win over nine-man Nacional in Montevideo for a 6-1 aggregate victory.
Nacional, overwhelmed by Cruzeiro, had 19-year-old central defender Sebastian Coates sent off in the 53rd minute and striker Gustavo Varela in the 69th.
Striker Vagner Love scored early in the second half for the visitors to dash Corinthians' hopes and 1981 winners Flamengo qualified on the basis of their 1-0 win in the first leg at the Maracana in Rio de Janeiro last week.
"We had the benefit of the rules and got result we needed. This is the tastiest defeat of my career," an elated Vagner Love told reporters.
"We weren't paying attention at the start of the second half. We fought, gave of our best and I think we deserved better luck. As I see it Corinthians were better (than Flamengo)," former Brazil striker Ronaldo said.
Estudiantes, for whom midfielder Leandro Benitez scored twice, could meet fellow Argentines Banfield in the quarter-finals unless Brazil's Internacional recover from a 3-1 deficit when the teams clash in Porto Alegre on Thursday.
