Brazil Serie A wrap: Fred fires for Fluminense
Fluminense striker Fred set up defender Leandro Euzebio for the opener four minutes before the interval, and the provider was then on the end of a pass from playmaker Thiago Neves on the stroke of half-time to double his side's advantage.
Nautico pulled one back from Kim eight minutes from the end, but the Serie A leaders held on to claim all three points.
The win leaves Fluminense five points clear of second-placed Atletico Mineiro, who have two games in hand, and take on third-placed Gremio on Sunday.
In other results, Palmeiras took a much-needed three points as they attempt to claw themselves out of the relegation zone when they scored a 3-1 win at Figueirense.
Thiago Heleno and Henrique had the visitors 2-0 up inside of 10 minutes - with both goals coming via Marcos Assuncao assists - but Aloisio breathed life into the match when he netted for the hosts in the 65th minute.
Two minutes later, however, Assuncao capped off a fine individual performance by getting his own name on the scoresheet to make sure of the win.
Palmeiras moved to 23 points with the victory, still five adrift of safety and with Flamengo - the team they need to overhaul - having two games in hand.And Portuguesa had a brace from Bruno Mineiro and another goal from Leo Silva to thank for their 3-1 away win over Santos.