Television pictures showed police using pepper spray to control fans at the Alligator Arena in Sete Lagoas which is being used as a substitute stadium while Belo Horizonte's Mineirao is rebuilt for the 2014 World Cup.
There was also trouble on Saturday when around 250 Cruzeiro fans gathered in front of the team's training ground to protest the relegation-threatened team's recent results.
Fans surrounded the players' cars as they arrived at the training ground and hurled insults, local media reported.
Souza, voted the championship's top player in 2009 when he was playing for Palmeiras, opened the scoring with a low shot five minutes before halftime and tapped in the second on the hour from full-back Fagner's cross.
Cruzeiro's misery was completed by a red card for defender Marquinhos Parana for a professional foul on Souza.
