Leaders Corinthians won 1-0 at Figueirense and were preparing to celebrate their fifth national crown when Bernardo scored a last-minute winner at the Engenhao in the Rio derby.
Corinthians have 70 points and Vasco 68 going into next weekend's final round of matches when a draw will be enough for the leaders if the two teams finish equal on points since they have won more matches than their rivals.
"It's going to be a very, very long week. It's tough. It's an historic derby because of the greatness of Corinthians and Palmeiras," Corinthians coach Tite told reporters.
With their nerves raw, Vasco had Leandro sent off from the bench for protesting and trying to attack the referee before Bernardo's winning goal brought relief and kept their title dream alive.
"I'm so happy to have helped, to have come on... it was a decisive moment and I always dreamt of experiencing a moment like that," said an emotional Bernardo.
Vasco, who won the Copa Brasil this season, are also in the semi-finals of the Copa Sudamericana, the region's second club competition, travelling to face Universidad de Chile on Wednesday in the second leg in Santiago with the tie poised at 1-1.
Fourth-placed Flamengo need a draw against Vasco to secure their place in next year's Copa Libertadores, South America's elite club championship.
