Corinthians and Vasco da Gama both won their Brazilian championship matches on Sunday to open a five-point gap over their closest title rivals with four matches remaining.Vasco, winners of the Copa Brasil early in the season and semi-finalists in the second-tier, regional Copa Sudamericana, beat Botafogo 2-0 in their Rio de Janeiro derby.Corinthians overcame relegation-threatened Atletico Paranaense 2-1 at home to stay top of the table with one more victory than Vasco and both on 61 points after 34 matches.Champions Fluminense and surprise team Figueirense -- enjoying their best season in the top flight -- are equal on 56 points with Botafogo and Ronaldinho\'s Flamengo, who lost 2-0 away to Coritiba, a point further back in fifth and sixth place.Vasco, under caretaker coach Cristovao Borges since Ricardo Gomes suffered a stroke during a match in August, had control throughout against Botafogo, even after they had midfielder Romulo sent off in the 76th minute for dissent.Felipe Bastos opened the scoring after 15 minutes with a low shot from outside the area before fellow midfielder Diego Souza had a penalty saved by Botafogo\'s international goalkeeper Jefferson.Central defender Dede started and finished off the move for the second goal on the hour, robbing the ball in midfield and dribbling past two rivals, passing left to Romulo as he went into the box and heading the return ball into the net.Corinthians appeared to be cruising to victory after scoring twice in the opening five minutes at the Pacaembu in Sao Paulo but 18th-placed Paranaense gave them a tough afternoon and might have snatched a point.    Midfielder Paulo Baier pulled one back four minutes after halftime, then Argentine striker Federico Nieto and Baier both hit the bar.Fluminense, who have won 10 of their last 15 matches, squandered a chance to remain close to the leaders on Saturday with a 2-0 home defeat to America Mineiro, another team in the relegation zone.It was the second surprise victory for America, who were bottom and virtually relegated at the end of last month before successive wins over Corinthians and Fluminense.However, they still need to win their remaining four matches to have a good chance of survival.