Defending champions Corinthians were ousted from the Copa Libertadores on Wednesday night, with a 1-1 draw in Brazil seeing six-time winners Boca Juniors advance to the quarter-finals 2-1 on aggregate.
Veteran playmaker Juan Roman Riquelme put Boca ahead in the 25th minute with a brilliant long-range shot which flew over the body of Corinthians goalkeeper Cassio Ramos.
That left Club World Cup champions Corinthians needing three goals to progress from the last-16 tie.
The hosts introduced former AC Milan forward Alexandre Pato in place of Romarinho at the start of the second half and equalised on the night through Paulinho's 51st-minute header, but could not make any further inroads.
"We are very happy because we were confident in the team we have," Riquelme told Fox Sports.
"We played a great first half and we knew the second was going to be tough as Corinthians were stepping forward."
Pato passed up a fine chance to set up a tense finish towards the end, and Boca goalkeeper Agustin Orion had to be on his toes to keep Carlos Bianchi's side on course to to claim a seventh Libertadores crown.
"We proved we want to be in top positions," Orion said.
"As Corinthians were losing, they were going to attack us a lot. We played a great match tonight."
Boca will host the first leg of the last-eight tie against Newell's Old Boys, possibly next Thursday.
Newell's prevailed 2-1 at Argentinian champions Velez Sarsfield on Wednesday to seal a 2-2 aggregate draw and win the tie on away goals.
Milton Casco's third-minute goal ensured Newell's got off to the perfect start, and the visitors doubled their lead four minutes before the break when Ignacio Scocco stole possession from defender Juan Sabia and beat Velez goalkeeper Sebastian Sosa at the second attempt.
Substitute Facundo Ferreyra struck seven minutes from time to give Velez hope, but they could not find any more goals and crashed out.
Information from the Press Association was used in this report.