In-form Internacional accounted for Luiz Felipe Scolari's Gremio 2-0 on Sunday, a day after defending champions Cruzeiro were held to a goalless draw by Criciuma.
Cruzeiro's run of consecutive draws has seen their lead atop the standings reduced to two points by International, who have won four games on the bounce.
Internacional's red-hot form continued on the weekend as they overcame Gremio in round 14 at the Estadio Jose Pinheiro Borba.
After a scoreless opening half, the home side broke the deadlock just past the hour-mark.
Chilean midfielder Charles Aranguiz rose above his marker on the edge of the six-yard box and snuck his header past Gremio goalkeeper Marcelo Grohe in the 62nd minute.
The result was put beyond doubt five minutes from time courtesy of substitute Claudio Winck, who pounced on a defensive error to cut inside the area and fire the ball low into the net.
Internacional have not conceded during their four-game winning streak, scoring eight goals in the process.
Corinthians spoiled Robinho's return to Brazil after edging 10-man Santos 1-0 on Sunday.
Robinho walked away empty handed in his first game for Santos since arriving from Milan on a year-long loan deal, as defender Gil stepped up to score an unlikely goal.
Gil leapt highest from a corner in the 84th minute to help third-placed Corinthians close the gap on Cruzeiro to three points.
Santos played the entire second half with 10 men after Alison was dismissed on the stroke of half-time.
Fourth-placed Fluminense drew 1-1 at home to cellar-dwellers Coritiba on Saturday, though they remain three points clear of Sao Paulo.
Former Milan striker Alexandre Pato bagged a brace as Sao Paulo downed lowly Vitoria 3-1 on Sunday.
All four goals came inside the opening 40 minutes at the Estadio Cicero Pompeu de Toledo, with Sao Paulo scoring the first three through Pato and Alan Kardec.
In other results, Flamengo climbed off the foot of the table thanks to Croatia international Eduardo's strike in their 1-0 win over Sport Recife.
Goias were beaten 1-0 at Bahia, while Atletico PR emerged 2-0 victors over Botafogo, who dropped into the relegation zone.
Jesus Datolo struck three minutes from time as sixth-placed Atletico Mineiro prevailed 2-1 at home to Palmeiras - leaving the visiting team without a win in eight league games.
Meanwhile, Figueirense moved out of the drop zone with a 1-0 success at Chapecoense.
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