Brazil Serie A wrap: Vasco return to winning ways
Alecsandro and Carlos Tenorio scored the goals for Vasco as they moved into fourth, while Portuguesa remain 13th.
Having not won in five matches, Vasco desperately needed a victory against Portuguesa and Alecsandro gave them the lead in front of their home fans in the 37th minute.
Portuguesa were reduced to 10 players three minutes later when Valdomiro received a straight red card and in the 48th minute, Vasco took advantage with Ecuadorian striker Tenorio doubling their lead after finishing off Juninho Pernambucano's good lead-up work.
The home side held on for the win despite losing Pipico to a red card in the 80th minute.
Bottom-club Figueirense fought back from two goals down to hold second-placed Fluminense to a 2-2 draw.
After a goalless first half, Fluminense scored just two minutes into the second half when Samuel Rosa set up Digao for the opening goal of the game.
Rafael Sobis made it 2-0 in the 53rd minute and Fluminense looked to be cruising towards their third win in four matches.
But Figueirense fought back at home with Aloisio scoring in the 68th minute and then Joao Paulo completing the home side's comeback with his goal three minutes from time.
The draw denied Fluminense top spot in the Brazil Serie A.
Instead they are tied on 44 points with Atletico Mineiro, who top the league based on more wins, and they have played two less matches than Fluminense.
In the other match, Palmeiras drew 0-0 with Gremio.