Copa Libertadores holders Atletico Mineiro kicked off the defence of their title with a 1-0 victory away to Zamora of Venezuela.
Former CSKA Moscow and Manchester City striker Jo headed home a Ronaldinho corner with three minutes to go to seal the win for the team from the Brazilian city of Belo Horizonte.
Defender Marcos Rocha said: "We came here to clinch a good result, we respected them more than enough. We did not know much about them. We started in an ideal way, with three points that puts us on the road to defend the title."
In Group Four's other match on Tuesday, Colombian giants Independiente Santa Fe defeated Nacional of Paraguay 3-1.
Midfielder Edison Mendez opened the scoring with an outstanding long-range shot in the 57th minute and Daniel Torres made it 2-0 with a superb individual effort two minutes later.
Nicolas Martinez pulled Nacional one goal back from the spot, but striker Jonathan Copete restored Santa Fe's two-goal lead on the counter-attack.
Returning Botafogo find winning form
Brazilian side Botafogo returned to the competition after a 17-year absence with a 2-0 win over San Lorenzo of Argentina at the Maracana stadium in Rio de Janeiro.
Juan Carlos Ferreyra fired in Botafogo's first close to the half-hour mark after San Lorenzo goalkeeper Sebastian Torrico could not hold midfielder Jorge Wagner's long-range effort. Wallyson made sure of the points with his side's second early in the second half.
San Lorenzo defender Santiago Gentiletti said: "Initially we could not get hold of the ball. In the second half we had more possession, but we could not threaten them. Nobody likes to lose, but we are going to go forward from here, I'm sure."
Man of the match Wallyson added: "I am happier with the triumph than the goal of mine. We are aware of the difficulties of the competition and so we fight in every match in order to win, no matter what the circumstances are."
"It is a very important triumph, we started on the right foot and now we can look forward to the next game more calmly," said Lucas Romero.
Finally, Mexican side Santos Laguna saw off Arsenal Sarandi of Argentina 1-0 in a Group Eight clash.
Oribe Peralta scored the only goal in the 19th minute after good work in the build-up from Darwin Quintero.