Brazil's Palmeiras defeated defending Copa Libertadores champions Liga Deportiva Universitaria 2-0 to leave the Ecuadorians on the verge of elimination.
After a goalless first half, Marcao took advantage of a mistake from goalkeeper Cevallos to open the scoring before Diego Souza's free-kick with eight minutes remaining sealed the win.
Palmeiras' Marquinhos and Liga's Luis Bolanos clashed in the closings stages and were both sent-off.
Palmeiras joined compatriots Sport and Chile's Colo Colo at the top of Group One with seven points, while Liga are three points adrift with just one game remaining.
"This was a key step after being eliminated in the Sao Paulo state tournament," said Palmeiras coach Wanderlei Luxemburgo.
Elsewhere, three-time champions Nacional of Uruguay secured their place in the last 16 after sharing a dull 1-1 draw with Peru's Universidad San Martin in Group Three.
In Lima, Marcos Mondaini put the visitors ahead with a close range finish after 74 minutes but with just two minutes remaining a free-kick from Argentinian playmaker Gonzalo Luduena maintained Universidad's hopes of reaching the knockout stage.
Nacional sit at the top of the table three points clear of Universidad, with Argentina's River Plate, who face Paraguay's Nacional tomorrow, four points further back.
In the final round of fixtures, River will host San Martin in Buenos Aires, while Nacional entertain Paraguay's Nacional in Montevideo.