A first-half penalty from Aviles Hurtado helped Monterrey to a 1-0 away victory over Morelia in the Liga MX semifinal first leg on Thursday in Estadio Morelos.
Hurtado won the foul in 37th minute in a game in which Morelia started the better side, but favorite Monterrey maintained a threat on the break.
Chilean Rodrigo Millar struck the crossbar in the fourth minute for Morelia, who attacked from the first whistle, but Monterrey weathered the early storm and generally looked comfortable at least until Morelia's late onslaught.
Rodolfo Vilchis also went close for Morelia from the edge of the area with six minutes left, as did Angel Sepulveda, who forced a sharp save from Monterrey goalkeeper Hugo Gonzalez in second-half injury time.
Colombian Hurtado -- the joint top scorer in the Apertura regular season -- limped off in the 65th minuted with what looked like a hamstring injury, something that will be of major concern for coach Antonio Mohamed ahead of Sunday's second leg in Estadio BBVA Bancomer.
Monterrey's city rivals Tigres take the advantage into Saturday's other second leg against Club America, following Wednesday's 1-0 victory in Estadio Azteca.