The unidentified man was shot in the throat and three others were hit by bullets in the gunfight that followed the game. The three were reportedly released from hospital but police could not be reached to confirm details.
The violence erupted after home side Vasco da Gama lost 1-0 to bitter rivals Flamengo.
Supporters threw home-made rockets and fireworks inside the ground and players were forced to sprint from the pitch to avoid being hit. Fans battled on the terraces and then continued to fight outside the ground.
The incident is the latest in a string of violence related to Brazilian football. Scores of people have been killed in recent years.
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(Reporting by Andrew Downie)
