The Pumas now have 23 points and are in 6th place in the standings, closing in on one of the spots in the eight-team playoffs that will determine the winner of the tournament title, reports Efe.
Santos Laguna, which has lost five matches in the tournament, has 29 points.
Diaz scored in the 5th minute of Sunday's match and Castillo added a goal in the 42nd minute.
Argentine Carlos Izquierdoz scored for Santos Laguna in the 78th minute, avoiding a shutout.
(This story has not been edited by Social News XYZ staff and is auto-generated from a syndicated feed.)
