Lisandro Lopez scored one goal and assisted two as Racing Club eased past Bolivar, while Robinho made his Atletico Mineiro bow.
Lisandro Lopez was on target as Racing Club opened their Copa Libertadores group stage campaign with a 4-1 demolition of Bolivar.
Former Argentina international striker Lopez, 32, scored the first goal of the match and assisted two others as Racing made light work of their Bolivian opponents in Group 3 on Wednesday.
Lopez, back at his boyhood club after making his name at Porto and Lyon, latched on to Oscar Romero's well-weighted pass in the 11th minute before lobbing the ball over onrushing goalkeeper Romel Quinonez from the top of the penalty area.
Roger Martinez doubled the advantage in the 28th minute and Rodrigo de Paul - on loan from La Liga outfit Valencia - made it 3-0 for Racing five minutes later after being set up by Lopez.
Lopez turned provider once again in the second half, this time squaring the ball to substitute Marcos Acuna seven minutes from time.
Bolivar salvaged some pride with two minutes remaining in regulation after Juan Arce found the back of the net.
Racing are two points clear of Deportivo Cali and Boca Juniors, who played out a goalless draw in Colombia.
Brazil international Robinho made his debut as Atletico Mineiro edged Independiente del Valle 1-0.
Back in Brazil after leaving Chinese champions Guangzhou Evergrande Taobao in February, 32-year-old Robinho came off the bench and replaced Juan Cazares approaching the hour-mark in Belo Horizonte.
Robinho entered the pitch with Mineiro already leading through Lucas Pratto's fourth-minute effort.
Mineiro are two points clear of Colo Colo in Group 5 after the Chileans saw off winless Melgar 1-0.