Internacional claimed their fourth successive win over arch-rivals Gremio by winning the so-called 'Gre-nal' match, one of Brazil's most fiercely-contested derbies, 2-1 on Sunday.
Internacional fans celebrated the win between the two Porto Alegre sides by cheering Gremio's beleaguered coach Celso Roth, taunting with him chants of "Stay, Roth."
Gremio, who twice hit the crossbar in the Gaucho championship match, went ahead when Tcheco converted a penalty in the 19th minute but Andrezinho levelled 14 minutes later from another spot kick.
Tempers flared during the second half as nearly all 22 players became involved in a pushing match that ended with red cards for Taison (Internacional) and Rafael Marques (Gremio).
With 12 minutes left, Andres D'Alessandro threaded a ball through for Indio to score the winner.
The defeat ended Gremio's hopes of winning the Gaucho, one of the regional tournaments that kick off the Brazilian season.
Striker Kleber Pereira scored a hat-trick, including an 88th minute penalty, to give Santos a 3-2 win at Ponte Preta that put them into the semi-finals of the Paulista championship.
Santos qualified on goal difference from Portuguesa as they joined Palmeiras, Sao Paulo and Corinthians in the last four.
Corinthians, already qualified, rested striker Ronaldo for their visit to Mirassol where they drew 2-2.