Atletico Nacional got off to a winning start in Group Eight with a routine 2-0 home win over Universidad de Chile.
Juan Valencia opened Atletico's account in the 22nd minute with a stunning left-footed volley, which tricked goalkeeper Johnny Herrera at his front post.
With 10 minutes remaining, Dorlan Pabon wrapped the game up with a powerful strike from close range.
In Montevideo, Defensor Sporting reacted positively to their opening loss against Velez Sarsfield by beating Deportivo Quito 2-0.
Brahian Aleman put the Uruguayans ahead from the spot in the 23rd minute, before Maximiliano Callorda secured the points 11 minutes from time with a well-taken finish.
In Group 4, six-time champions Boca Juniors, making their first tournament appearance in three years, were held to a 0-0 draw by Zamora.
Boca debutant Santiago Silva came closest to opening the scoring late on when he rattled Alvaro Forero's post with a header.
After the game, there were reports of a heated argument between Juan Roman Riquelme and coach Julio Cesar Falcioni, while rumours of Falcioni qutting dominates today's news.
Last night's results:
Zamora 0-0 Boca Juniors (Group 4)
Defensor Sporting 2-0 Deportivo Quito (Group 7)
Atletico Nacional 2-0 Universidad de Chile (Group 8)
Tonight's fixtures:
The Strongest v Santos FC (Group 1)
Lanus v Flamengo (Group 2)
Deportivo Tachira v Corinthians (Group 6)
