Boca Juniors, Cruzeiro and Colo Colo won the first leg of their Copa Libertadores last-16 ties on Wednesday.
Ramon Abila and Mauro Zarate were on target in the first half as Argentine giants Boca defeated visiting Libertad 2-0 in Buenos Aires midweek.
Six-time winners of the South American showpiece tournament, Boca opened the scoring after seven minutes when Abila fired a shot past Libertad goalkeeper Rodrigo Munoz.
Former West Ham, Lazio and Fiorentina forward Zarate doubled the lead against the Paraguayan side two minutes before half-time with a terrific solo effort.
Cruzeiro trumped hosts Flamengo 2-0 in an all-Brazilian affair in Rio de Janeiro on Wednesday.
Goals from Uruguay international Giorgian De Arrascaeta and Thiago Neves silenced Flamengo and put Cruzeiro in the box seat.
Chilean powerhouse Colo Colo, meanwhile, edged 10-man Corinthians 1-0 on home soil.
Colo Colo hit the front thanks to Carlos Carmona's 38th-minute opener – the veteran midfielder converting the rebound.
Brazilian visitors Corinthians ended the match with 10 men after Gabriel was sent off nine minutes into the second half.
