[2] The draw for the first stage was held on 17 December 2018, 20:30 PYST (UTC−3), at the CONMEBOL Convention Centre in Luque, Paraguay.
If still tied, extra time was not played, and a penalty shoot-out was used to determine the winner (Regulations Article 27).
Tied 1–1 on aggregate, River Plate won on away goals and advanced to the second stage.
Tied 1–1 on aggregate, Sol de América won on penalties and advanced to the second stage.
Tied 1–1 on aggregate, Unión La Calera won on away goals and advanced to the second stage.
Tied 2–2 on aggregate, Independiente del Valle won on penalties and advanced to the second stage.