On a day of derbies all across Brazil, the former Santos and Wolfsburg striker scored Flamengo´s first nine minutes into the second half before doubling their lead a quarter of an hour later.
In the first leg of the Sao Paulo state championship final, Sao Paulo drew 0-0 at home to Corinthians in front of almost 58,000 fans, while Internacional and Gremio were also scoreless in Rio Grande do Sul.
O Globo reported that 14 fans were injured, three of them from gunshot wounds, in clashes between Sao Paulo and Corinthians fans before the game at the Morumbi stadium.
Cruzeiro beat Atletico Mineiro 2-1 in the first leg of the Minas Gerais state final in Belo Horizonte.
Marquinhos Gabriel put Atletico ahead on the stroke of halftime only for Ricardo Oliveira to equalise for the away team 10 minutes into the second half.
Leo got Cruzeiro's winner on the hour mark when he finished off a move from a corner kick.
The second legs of the state championship matches will take place next weekend.
Brazil's national league, the Serie A, begins on April 27.
(Reporting by Andrew Downie; Editing by Christian Radnedge)
