Luis Hernandez, the top scorer in the previous tournament two years ago in Bolivia, also began on the right note by netting the goal that gave Mexico a 1-0 victory over Chile in the match that preceded Brazil's debut in Ciudad del Este.
But both were upstaged by the 19-year-old Brazilian Ronaldinho, who scored a memorable goal two minutes after coming on as a substitute in the 7- 0 thrashing of Venezuela.
Ronaldinho collected a pass and, without letting the ball touch the ground, flicked it over a defender, swept past another Venezuelan and blasted the ball between the goalkeeper, Renny Vega, and his near post.
By that stage, Brazil were already four goals ahead in their Group B first round match, Venezuela paying the price for trying to play an offside trap they clearly had not mastered.
Venezuela, who had arrived with hopes of improving on a dismal past record, held out for 27 minutes and even caused Brazil some awkward moments early on with an attack led by the Argentina-based Daniel Noriega. But their defence collapsed when Ronaldo, whose two goals gave him an ideal start to an tournament that he hopes will help him to forget an injury-plagued season in Europe, fired home from close range. Amoroso helped himself to two goals while Rivaldo and Emerson Ferreira grabbed one each.
The win will help Brazil forget a week in which Leonardo walked out, generating rumours of discontent in the camp at the methods of the coach, Wanderley Luxemburgo.
Brazil's next match will be on Saturday against Mexico, who started by claiming three points against a disappointing Chile.
Their winner came when Hernandez, who scored six goals in Bolivia and five more in last year's World Cup, calmly slotted the ball home in the 60th minute after being superbly set up by a defence-splitting pass from Cuauhtemoc Blanco, who also had an excellent game.
Their slick partnership was a stark contrast to Chile's "Za-Sa" strikeforce of Ivan Zamorano and Marcelo Salas who, deprived of good service, had subdued games.