Copa Libertadores finalist Gremio have been spying on opponents throughout the 2017 season, according to ESPN Brasil.
Argentina's Lanus have never taken part in a Copa Libertadores final, and they're out to prove they belong against two-time winners Gremio of Brazil.
The Copa Libertadores had seen a comeback for the ages the night before, but Gremio wouldn't allow another one on their home turf.
"It was a clear penalty. I prefer that a referee continues to make mistakes but not that seven judges are mistaken," River coach Gallardo on VAR.
River had the edge from the first leg and then scored twice Tuesday night. But Lanus wasn't rattled, and banged in four unanswered goals to advance.
Barcelona of Ecuador has topped three Brazilian clubs in Copa play, but a fourth might be out of range after they fell 3-0 to Gremio in the first leg.