Juan Carlos Cacho scored an 84th-minute penalty to send Unam Pumas through to the semi-finals of the Mexican Apertura with an upset 2-0 win at ten-man Cruz Azul.
Cruz Azul held a 2-1 advantage heading into the second leg on their home turf, but they immediately conceded when Martin Bravo netted with just a minute played.
The home side's grip on the tie was further loosened when Horacio Cervantes was sent off just before the break before Unam Pumas completed the against-the-odds win from the penalty spot via Cacho.
Club America secured their passage in far easier circumstances as they thrashed San Luis 4-1, after holding their rivals to a goalless draw in the first leg.
Club America scored three times in the opening half to put the tie beyond doubt, with Vicente Sanchez, an Anibal Matellan own goal, and Enrique Esqueda on the scoresheet.
Diego De la Torre pulled a goal back but it did not inspire a comeback and Vicente Vuoso sealed a comfortable night for the hosts.