It was the school's 18th title, won with the help of some 4,300 participants in the sumptuous parade.
Fans of the samba school, which is rooted in Rio's Mangueira favela, screamed with joy as the results were read out.
In an indication of how high the stakes are in the carnival championship, the results came in an armoured car.
One of Rio de Janeiro's most traditional samba schools, Mangueira, has won this year's Carnival.