Vladimir Marin scored twice as Paraguayan giants Olimpia edged out Ecuador's Elemec in the first leg of their Copa Sudamericana second stage tie.
Left winger Marin opened the scoring after 14 minutes, directing home a Pablo Zeballos cross.
And he restored their advantage with 18 minutes to go after Nicolas Vigneri had levelled six minutes before the interval after some slack defending from the home side.
The second leg will be played on Tuesday in Guayaquil.
In a clash between two Colombian sides, Santa Fe and Cali drew 1-1 in the capital Bogota.
Omar Perez scored from the penalty spot in the 57th minute for Santa Fe but Cali conjured up an equaliser through Breiner Belalcazar four minutes from time.