At this time of the season national leagues in South America and Copa Libertadores are running at the same time. It's usual that teams involved in Copa Libertadores are playing weakened or reserve teams in national competition.
And when they do that - they do it with style
Also, there are few sides involved in national cup competition, so there is also possibility that something will pop up.
Sport Recife, Botafogo and Vasco da Gama are playing national cup semi finals on Wednesday, while Santos, Fluminense and Sao Paolo are playng Copa Libertadores on the same day.