A second straight win for Unam Pumas moved them up to fifth in the Apertura table.
The 1-0 victory against Pachuca came courtesy of substitute David Izazola's goal six minutes from the end.
Elsewhere Jaguares and Guadalajara shared the spoils in a 1-1 draw, Luis Rey's 66th minute strike cancelling out Antonio Gallardo's 41st minute opener.
Guadalajara were reduced to ten-men before the end when Hector Reynoso was sent off and he will miss their next game.
Information from the Press Association was used in this report.