Twice South American champions Cruzeiro, runners-up last year, crushed Chile's Colo Colo 4-1 in a Group Seven match at the Mineirao in Belo Horizonte. Kleber converted a pair of penalties while Colo Colo had two men sent off.
Flamengo also got the better of Chilean opposition with a 2-0 win over Universidad Catolica in a Group Eight encounter at the Maracana. Vagner Love also missed a late penalty for the Brazilians.
Corinthians, with former World Cup winners Ronaldo and Roberto Carlos in their ranks, beat Uruguay's Racing 2-1 at the Pacaembu in Group One.
Looking to win the trophy for the first time in their centenary year, the Brazilian side were stunned when Racing striker Martin Cauteruccio stole in behind the defence to net Rodrigo Brasesco's free kick with 52 seconds on the clock.
Ronaldo began the move that led to Corinthians' 11th minute equaliser, feeding playmaker Tcheco whose excellent pass left Elias with only the keeper to beat.
"It's going to be a very tough competition, but we're prepared for that," Ronaldo told reporters after only his second match this year because of injury.
Cruzeiro, beaten 2-0 away by Argentina's Velez Sarsfield two weeks ago, were whistled by their fans after the first half finished 1-1. Chile striker Esteban Paredes tapped in an equaliser from a low left cross in reply to Thiago Ribeiro's seventh-minute opener for the Brazilian team.
Between the 68th and 71st minutes, Colo Colo had Roberto Cereceda dismissed for a second yellow card offence, Pedro Ken scored Cruzeiro's third goal and Kleber made it four with his second penalty.
Adriano increased the home side's lead after a fine attacking run by Leo, and Vagner Love should have made it three but blasted a penalty over the bar.
