The first and only goal came after 23 minutes when Ronaldo could only turn into his own net from a corner.
Madrid had chances in the second period, but could not make the breakthrough as the home side held on for a famous win.
Here, Sports Mole dissects the 90 minutes of action between the two Spanish teams.
On target: 0
On target: 4
Was the result fair?
On the balance of play, a point would have been just about a fair result this evening. Madrid were as poor as they have been all season, but the fact Granada did not register a single shot on target tells you everything that you need to know about their attacking threat. The home side defended superbly, however, and if it was down to pure effort, then they deserved all three points.
It wasn't the most attacking of performances from the home side, but their players and supporters will not mind for one moment. They defended superbly all evening despite coming under pressure in the latter stages. They rode their luck at times in the second period, but will feel that they were worthy of the three points.
Real Madrid's performance
Jose Mourinho's side were just about as poor as they have been all season. They started the match slowly, but you always expected them to respond in the second period. Even when Granada continued to drop deeper and deeper, they could not find that elusive final pass. It appears that the midweek clash against Barcelona took a great deal from them, both mentally and physically.
Sports Mole's man of the match
Diego Mainz: It was a close one with fellow defender Allan Nyom, but Diego Mainz just picks up the accolade due to his pure defensive ability. The 30-year-old used all his experience in the final stages to settle his defence, while his heading was as impressive as you are ever likely to see.
Biggest gaffe of the match
Karim Benzema had a glorious chance to level for Madrid late on when he was presented with an open goal, but somehow he fired wide of the target from close range. It was a quite incredible miss from the Frenchman.
Antonio Mateu had a fairly productive 90 minutes of action this evening. He was not called into action on too many occasions, but was perhaps lenient in the second period when he decided against sending Luka Modric from the field, despite the Croatian handling moments after receiving a yellow card.
Granada: Granada will attempt to continue their winning run when they travel to fellow strugglers Deportivo La Coruna next weekend.
Real Madrid: Next up for Real Madrid is a home clash against Sevilla next Saturday before they welcome Manchester United in the Champions League on February 13.