Hosting Sao Paulo in the first leg of the semifinals of the 2010 Libertadores Cup, Internacional won 1-0 on Wednesday.
The defeat marks Sao Paulo's fifth-straight loss since the conclusion of the World Cup in South Africa.
Out-playing Sao Paulo during most of the match, Internacional was only able to score one goal. The game-winner came from Giuliano in the 68th minute, having entered the match just minutes before.
Dominating the ball with his back to the goal, Giuliano spun around and slammed the ball into the lower left side of the Sao Paulo goal.
Internacional hold the advantage in the return leg at Sao Paulo on August 4. The team needs only to produce a draw in next week's match in order to advance to the finals of the competition.