Flamengo, the club the former FIFA world player of the year walked out on last week, beat Coritiba 3-1 at home in Rio for their first victory after three draws since the championship kicked off last month.
Ronaldinho, who failed this season to repeat his good performances for Flamengo last year that earned him a return to the Brazil side, played in his old central midfield position, taking part in several good attacking moves.
Now wearing number 49, his sick mother's year of birth, Ronaldinho was also a danger with free-kicks and corners but he had no part in the only goal of the match at the Pacaembu stadium in Sao Paulo.
Former Manchester City and Brazil striker Jo headed the winner three minutes after halftime to give Mineiro 10 points from four matches, one point more than Vasco da Gama, who visit Bahia on Sunday.
Mineiro, from the city of Belo Horizonte, surprisingly signed Ronaldinho until the end of the year, hoping the 32-year-old's penchant for night life would remain at Flamengo and he would regain some of the form that made him the world's best player when he was al Barcelona.
Ronaldinho only won one title with Flamengo, the Carioca (Rio) state championship after joining them from AC Milan in January 2011.
