Pumas UNAM move clear, Nacional stay top
It was a top-of-the-table clash on Thursday as Pumas welcomed Tachira to Estadio Olimpico Universitario de Colimo and the Mexicans came out on top thanks to Sosa's second-half brace.
Leading 1-0 at half-time via Uruguayan defender Gerardo Alcoba's close-range finish in the 31st minute, Hibert Ruiz doubled the advantage eight minutes after break.
Ruiz fired a low shot past goalkeeper Jose Contreras before Sosa made it 3-0 eight minutes later.
Edgar Perez Greco pulled a goal back for the Venezuelans with eight minutes remaining, but Sosa swiftly restored Pumas' three-goal lead four minutes later after Francisco Martinez squared the ball into the six-yard box.
Pumas top the group with nine points from four matches, three clear of Tachira.
Olimpia and Emelec are five points off top after the former triumphed 4-2 thanks to two late goals from Fredy Bareiro and Luis Caballero.
Nacional remain top of Group 2 following their 1-0 win at home to Palmeiras.
Nicolas Lopez's goal five minutes into the second half was all that separated the two teams as Nacional stayed unbeaten with two wins and two draws.
Palmeiras dropped to third, three points behind Rosario Central, who rallied to beat River Plate Montevideo 3-1 away from home.
Meanwhile, Group 3 leaders Racing Club overturned a two-goal deficit to draw 2-2 at Deportivo Cali, in a match that saw both sides finish with 10 men.