Ronaldinho's Fluminense suffered their fifth defeat of the Brazilian Serie A season with a 1-0 loss to Avai.
Andre Lima struck the winner in Saturday's match at Avai's Ressacada stadium in Florianopolis, firing in from close range in the sixth minute, reported Xinhua news agency.
Ronaldinho played the full 90 minutes in just his second match for the Rio de Janeiro football club since his move from Mexico's Queretaro last month.
Despite the result, Fluminense remain third in the standings with 30 points while Avai were at the 13th spot.
Fluminense will meet Internacional in their next match on Wednesday and Avai will play Ponte Preta on Thursday.
