Luiz Felipe Scolari's Gremio showed no mercy against rivals Internacional, with Argentinean substitute Alan Ruiz scoring twice in a 4-1 rout at the Arena do Gremio on Sunday.
Gremio's big win saw them leapfrog Internacional, Atletico Mineiro and Corinthians into third position with 57 points from 33 rounds.
The two-time Serie A champions (+12) are level on points with Mineiro (+11) but ahead on goal difference and clear of Corinthians (+17) due to their superior number of wins, which is 16 to 15.
Tiago Pagnussat and Dodo led Mineiro to a 2-0 victory at Palmeiras on Saturday, while Corinthians edged Santos 1-0 the following day.
Gremio were on a four-game unbeaten streak prior to kick-off and they wasted little time asserting their dominance against Internacional.
Luan set the tone in Porto Alegre, slotting the ball into the net from close range in the 28th minute after some neat work by Dudu.
Ramiro doubled the home side's advantage four minutes into the second half, running between two Internacional defenders and slotting the ball underneath goalkeeper Alisson.
Internacional substitute Rafael Moura pulled a goal back just past the hour-mark, but that is as good as it got for the visitors.
Ruiz - on loan from Argentine outfit San Lorenzo - came off the bench and completed the scoring with a quick-fire brace, scoring twice in six minutes.
He headed home his first goal from a corner in the 76th minute before making it two from the edge of the area six minutes later as tempers flared late on.
Defending champions Cruzeiro are five points clear at the summit with five matches remaining after overturning a half-time deficit to beat basement side Criciuma 3-1.
Lucca's third-minute strike gave Criciuma a shock 1-0 lead at the break, but Cruzeiro stepped it up a gear in the second half with three unanswered goals.
Bolivian star Marcelo Moreno came off the bench and equalised in the 59th minute, before Ricardo Goulart and Willian inspired a 20th league win.
Sao Paulo are five points behind following their hard-fought 2-1 win at Vitoria, who are two points adrift of safety.
In other results, Fluminense's four-game winning streak came to an end after they lost 1-0 against Coritiba, who climbed out of the relegation zone.
Sport Recife scored twice in the final minute as they snatched a 2-2 draw at home to Flamengo and Cleo's brace helped Atletico PR to a 2-0 win over third-bottom Botafogo.
Figueirense downed Chapecoense 1-0, while Goias accounted for second-bottom Bahia 3-0.
