Velez Sarsfield and Libertad booked a place in the quarter-finals of the Copa Libertadores, taking down Atletico Nacional and Cruz Azul respectively.
Velez, 1-0 winner in Colombia last week, stretched its overall lead in the 52nd minute when Augusto Fernandez prodded home the rebound after Alejandro Cabral's shot had hit the post.
Luis-Fernando Mosquera's free-kick midway through the second half gave Atletico hope and ensured a nervy ending for the host, but it held on.
Velez midfielder Francisco Cerro accepted his team had not had it all its own way.
"Nacional are a talented team, difficult to mark," he told Fox Sports. "We were unable to impose our style on the field during the 180 minutes of the tie."
"In Colombia, we played more defensively. Tonight, more offensively, but I highlight we were organised."
Next up for Velez will be defending champion Brazil's Santos or Club Bolivar. The Bolivian side leads 2-1 after the first leg.
Meanwhile, Paraguay's Libertad booked its ast eight spot with a 2-0 home victory over Mexico's
Libertad was on the front foot from the outset at the Estadio Nicolas Leoz as it looked to press home its advantage after a 1-1 draw in last week's away leg.
And it got its reward in the 10th minute when
Another free-kick by Ayala five minutes into the second half was met by
Corona kept the scoreline respectable for
Ayala told Fox Sports that the draw in
"We knew the result in the first match was crucial and tonight we did a good job," he said.
"We waited for
"We are in quarter-finals, but now we hope we can get further in the tournament."
Libertad will face either Universidad de