Santos secured a 2-1 win over Jaguares in the second leg of its Clausura quarterfinal to seal a 6-4 aggregate victory and book a place in the last four.
After a 4-3 win in the first leg, Santos allowed Jaguares to take the lead after seven minutes through Armando Zamorano, leveling the aggregate score.
But Santos, which finished with the best record in the regular season, responded with goals from Carlos Quintero and Oribe Peralta to see off Jaguares before halftime.
Tigres will meet Santos in the next round after topping Morelia, 4-1, in the second leg for a 5-1 aggregate win.
Morelia trailed 1-0 after the first leg and the second leg remained scoreless until the 64th minute when Hugo Ayala opened the scoring for Tigres, with goals from Lucas Lobos and substitute Edno Cunha quickly following to give Tigres a comfortable cushion.
The other semifinal will feature Monterrey taking on America.
Monterrey topped Tijuana, 4-3 on aggregate, with Jose Basanta netting the winning goal in the 65th minute on Saturday, while America lost the second leg of its quarterfinal to Pachuca, 1-0, but still did enough to reach the semifinals with a 3-2 aggregate triumph.