Club America lost, 3-1, in its second leg, quarterfinal match against Costa Rica's Alajuela on Wednesday but advances 5-3 on aggregate to an all-Mexican final four.
Club America, which won 4-0 at Azteca Stadium last week, faces Toluca. Morelia meets Necaxa. First- and second-leg games for both series are tentatively set for April 30 and May 7.
Never in the competition's 41-year history have all four semifinalists come from the same country.
After Santiago Fernandez gave Club America a 10th minute league, Pablo Chinchilla, Erick Scott and Wilmer Lopez scored for Alajuela.
MLS's representatives Los Angeles and Columbus fell at the quarterfinal stage to Necaxa and Morelia, respectively. New England and San Jose fell in the previous round to Municipal (Guatemala) and Alajuela, respectively.