The match has been re-scheduled for 19:45, but the reigning champions' head coach would rather have seen an earlier start
The league encounter was initially scheduled for Sunday evening, but was postponed after stadium lighting wires were cut by vandals before the game.
The match has now been re-arranged for Monday 19:45CET, but Mourinho would rather have seen a kick-off at an earlier stage.
"Given how tight the schedule is, it is best to play the game on Monday and at 17:00, because we are not assured that by 20:00 [when it is dark] the problem will be resolved," Pardeza told reporters.
"That is the time that Mourinho asked for and that we supported."
Meanwhile, Madrid have released an official statement on their official website to explain their wish for the game to be played during the day.
"After the deplorable events that took place yesterday, Sunday, and led to the suspension of the Rayo Vallecano-Real Madrid match, Real Madrid asked the Professional Football League (LFP) to schedule the game today, Monday, during the day in order to avoid any potential problems that might again put it at risk.
"The president of the LFP has decided, however, that the match will be played at 19:45 and has accepted personal responsibility for it to take place without incident.
"Real Madrid base their request on their concern for the lack of dates for the rescheduling of the match should it not be possible for the match to go ahead today."
Madrid currently sit 16th in the Liga table with four points from as many games, while Rayo are seventh.