Tigre recorded an important 2-1 win over Olimpia in the first leg of their Copa Libertadores round-of-16 tie on Tuesday.
Argentine outfit Tigre hosted the first leg in Buenos Aires and goals from Gabriel Penalba and Matias Perez Garcia put them in control just after the hour-mark.
Herminio Miranda pulled a goal back for Paraguay's Olimpia with 12 minutes remaining, a strike which could be important heading into the second leg on May 16.
Olimpia were unlucky not to have been awarded a penalty midway through the first half when a Fredy Bareiro header appeared to strike the arm of Mariano Echevarria.
Just five minutes later, Tigre were ahead thanks to a fine Penalba goal.
Alejandro Donatti rose above his marker to win a header inside the area and, on the turn, Penalba volleyed into the bottom corner to put his side ahead.
Tigre doubled their advantage on 64 minutes as Garcia was left unmarked in the middle of the penalty area, allowing him to header a pinpoint Ramiro Leone cross into the bottom corner.
Olimpia were given a way back into the tie thanks to Miranda, whose 78th-minute effort was the pick of the three goals.
The defender curled a delightful 35-yard free-kick into the top corner, leaving a scrambling Javier Hernan Garcia with no chance.
In the day's other game, Palmeiras are in a strong position to advance after securing a 0-0 draw at Tijuana in their first leg.
The teams will head to Brazil for the second leg on May 14.