Lucas Barrios scored a hat-trick as Gremio stayed undefeated in the Copa Libertadores, while River Plate preserved their 100 per cent record.
Former Borussia Dortmund forward and Paraguay international Barrios recorded a three-goal haul in Gremio's 4-1 rout of 10-man Guarani on Thursday.
Barrios' man-of-the-match performance saw Group 8 leaders Gremio improve to 10 points after four matchdays, three points clear of Guarani.
A recruit from fellow Brazilian side Palmeiras, Barrios hit the ground running with two goals inside 28 minutes, including the opener from close range in the eighth minute.
Barrios doubled the lead 20 minutes later when he silkily controlled the ball, leaving his opponent in no-mans land, before placing his shot underneath Guarani goalkeeper Alfredo Aguilar.
A Leo Moura own goal in the 34th minute gave Guarani some hope but Pedro Geromel's strike in first-half stoppage-time restored Gremio's three-goal advantage after Nestor Camacho was sent off for the visitors.
Barrios completed his hat-trick with 11 minutes remaining after springing the offside trap and firing the ball into the net.
Argentine giants River Plate came from behind to beat Emelec 2-1.
After Ayrton Preciado gave Emelec a second-minute lead at home, River hit back via Jorge Moreira and Lucas Alario.
The result made it three wins from as many matches for River in Group 3.
Nacional made light work of Chapecoense, easing to a 3-0 victory in Group 7.
Chapecoense ended the trip with nine men as Nacional ended the day level on points with Lanus, who were held to a 1-1 draw by Zulia.
Meanwhile, leaders Godoy Cruz accounted for 10-man Sport Boys 3-1 to remain unbeaten in Group 6.