Corinthians took a narrow lead in the first leg of the Recopa Sudamericana with a 2-1 win at Brazilian compatriots Sao Paulo.
The Morumbi stadium saw the reigning FIFA Club World Cup and Copa Libertadores champions Corinthians come out on top against Copa Sudamericana champions.
Corinthians took the lead in the first half through Paolo Guerrero, then, after Aloisio levelled at the start of the second period, Renato Augusto scored the decisive goal from distance for the visitors.
Corinthians ran into trouble in the first half when midfielder Danilo collided with Sao Paulo's Rodrigo Caio and was forced to leave the field with a knee injury.
Douglas replaced him in the 27th minute and sixty seconds later, Corinthians took the lead when Peruvian striker Guerrero beat keeper Rogerio Ceni after good work from Romarinho and Emerson.
Sao Paulo coach Ney Franco made attacking substitutions during the break as Wellington and Aloisio came in for Douglas and Paulo-Henrique Ganso and the team quickly saw their form change.
One minute after the interval, Aloisio got the ball outside the box and shot over Cassio's body. The keeper touched the ball but could not stop the goal.
Midway through the second period Augusto got the ball in midfield and, spotting Rogerio Ceni off his line, fired over the keeper to make it 2-1.
The tie remains in the city of Sao Paulo for the second leg, switching to the Pacaembu on 17 July, with Corinthians still needing a draw as the away goals rule is not in operation.
Corinthians defender Paulo Andre told Lancenet.com.br: "We had more opportunities and should have taken advantage of them.
"This is a good win. Now we take the tie to our home. The result is important, but we must play the return match the same way we did tonight because nothing is defined."
Sao Paulo midfielder Jadson, meanwhile, understood the reaction from fans who booed them after the end of the game.
"We did not expect this result," he said. "We did not play well.
"We have to work hard to correct errors. Fans have the right to protest and we must fix some things."