The home side opened the scoring on 43 minutes with a bizarre goal from Diego Souza, and made the game safe with a second on 79′, coming from Elton.
After the first legs of each of the four ties containing Brazilian sides, Vasco, Botafogo, Ceara and Flamengo look well placed to reach the next stage.
The second leg of Vasco v Palmeiras takes place on August 25. The winning side will play either Club Aurora or San José of Bolivia, or Nacional of Paraguay, in the next round.
