In the other Thursday matches, Paraguayan champion Libertad came from behind to win at Brazil's Parana, 2-1, while Nacional of Uruguay beat Mexico's Necaxa, 3-2, in Montevideo.
On Wednesday, Santos' bid to break the Libertadores Cup record for consecutive wins failed when it was held to a 2-2 tie at Venezuela's Caracas.
Boca Juniors crushed Velez Sarsfield, 3-0, on goals by Juan Roman Riquelme, Martin Palermo and Clemente Rodriguez in an all-Argentine clash.
In other first-leg matches, Sao Paulo edged Gremio, 1-0, in a battle of Brazilian clubs. Mexico's America routed Chile's Colo Colo, 3-0, and Uruguay's Defensor Sporting beat Brazil's Flamengo 3-0.