Brazil's most popular derby between old enemies Fluminense and Flamengo ended goalless at the Maracana in the first leg of their Copa Sudamericana preliminary stage clash.

The two teams fielded largely second-string line-ups as both coaches make the Brazilian championship their priority.

Flamengo had a chance to go in front early on as Denis Marques was denied by the right-hand post of Fluminense goalkeeper Rafael, with Airton also hitting the woodwork five minutes later.

The second leg of this tie will be played on August 26, also at the Maracana, with Flamengo as the home team.

''In the second game, we should pay more attention and aim to make fewer mistakes. Maybe they are common because we have not played together so much, but they were too many sometimes,'' said Flamengo midfielder Emerson.

''The team ran quite a lot, and put in a lot of effort. That is what counts too.''

Fluminense right-back Mariano believes his team have what it takes to beat their arch-rivals: ''There are two matches. Nothing is definite,'' he said.

In Paraguay, hosts Cerro Porteno beat Bolivia's La Paz FC 2-0, with Argentinian striker Roberto Nanni opening the scoring in the 21st minute.

Jorge Britez widened the gap 10 minutes into the second half, with the return match being played next Thursday in Bolivia.