PSG host relegation battling Le Havre on Saturday
Cristiano Ronaldo scored his first goal in five league games to put Real ahead in the 27th minute but in the second half had a penalty saved by Diego Alves, who turned away a league-record sixth spot kick of the campaign.
Marcelo quickly restored Real's lead, however, by cutting inside from the left-hand side of the area and curling the ball under Alves with his weaker right foot, keeping Real on course for a first title since 2012.
Granada's run of six consecutive seasons in La Liga ended following a 2-1 defeat at Real Sociedad, leaving Tony Adams's side 10 points adrift of safety with three games left. They join basement club Osasuna in the Segunda Division next season.