Corinthians are close to qualifying for the last 16 after Ronaldo opened the scoring in the 39th minute and Chicao made it 2-0 in the second half with a free-kick.
He said: "We must take profit from playing at home in the best way possible and that is by gaining the three points. We could have controlled the game better, but the important thing is that the final result is ours."
In Colombia, 2004 champions Once Caldas beat Paraguayan side Nacional 1-0 to reclaim the lead in Group Two. Jhon Valencia netted the winner with a free-kick and the Colombian side will now determine their fate by facing Sao Paulo in Brazil.
If Once Caldas do not lose on 21 April, they will progress to the last 16 as group winners, while a defeat will see Sao Paulo into the next phase and leave the Colombian team waiting to see if they are one of the best six group runners-up to progress.
In Guayaquil, Deportivo Quito won the duel between Ecuadorian teams as a last-gasp penalty from Ivan Hurtado gave them a 1-0 win over compatriots Emelec 1-0 in Group Five.