[1] A total of 16 teams competed in the final stages to decide the champions of the 2018 Copa Libertadores.
Tied 2–2 on aggregate, Colo-Colo won on away goals and advanced to the quarterfinals (Match S2).
Tied 3–3 on aggregate, Grêmio won on penalties and advanced to the quarterfinals (Match S4).
[13][14] Tied 2–2 on aggregate, River Plate won on away goals and advanced to the finals.
In the finals, if tied on aggregate, the away goals rule was not used, and 30 minutes of extra time were played.
If still tied after extra time, a penalty shoot-out was used to determine the winner (Regulations Article 30).