Oscar and Leandro Damiao, who were both named in Brazil's 18-man squad for the London Olympics earlier this week, grabbed Internacional's goals in the first half, with Leo's second-half strike scant consolation for the visitors.
The victory moved Inter a point behind leaders Atletico Mineiro and Vasco da Gama, and level on points with third-placed Fluminense. The top three play on Sunday.
Elsewhere on Saturday, Cidinho netted twice before half-time to set Botafogo on their way to a 3-0 triumph over Bahia, Elkeson putting the result beyond doubt with a third goal three minutes after the interval.
Bottom-of-the-table Atletico Goianiense remained winless after going down 1-0 at home to Nautico Recife, Araujo scoring the game's only goal after 23 minutes.