Cruz Azul could only manage a 0-0 draw in Estadio Azul against Mexico City rival Club America on Thursday in the 2017 Apertura quarterfinal, despite Las Aguilas finishing the game with nine players.
Club America's Mateus Uribe was shown a straight red after half an hour, with Edson Alvarez given his second yellow in the 90th minute, while Cruz Azul goalkeeper Jesus Corona saved a penalty from Mexico teammate Oribe Peralta in the 36th.
Cruz Azul started the brighter side and was pushing for an opener in an end-to-end game, before Uribe was sent off for a high tackle on Julio Dominguez.
The red card actually seemed to improve America, who went close close in the 36th minute through a Pablo Aguilar effort from close range.
Aguilar won a penalty seconds later when Dominguez was adjudged to have dragged him down, but goalkeeper Corona saved Perata's spot-kick to stop America gaining a vital away goal.
Cruz Azul dominated the second half and Felipe Mora forced a fine save from America keeper Agustin Marchesin with 15 minutes to go, but Las Aguilas' defense remained resolute and held out for the goalless draw.
In Thursday's other quarterfinal first leg, Argentine Rogelio Funes Mori netted twice in the first half as Monterrey defeated Atlas 2-1 in Estadio Jalisco.
Regular season first placed team Monterrey took the lead in the sixth minute, when Atlas midfielder Javier Salas gifted the ball to Dorlan Pabon inside the penalty area, with the Colombian squaring for Funes Mori to tap in.
Monterrey doubled its lead in the 18th, with Funes Mori again finding a close-range finish from a Pabon pass.
Atlas responded through Christian Tabo, who drove a shot into the top right angle of goal from outside the penalty area 10 minutes before half-time.
The second leg will take place on Sunday in Monterrey, with the deciding leg between Cruz Azul and America also on Sunday.