The World Player of the Year opened the scoring early on with a dipping effort from the edge of the area and repeated the trick just after half-time with another rasping drive that found the top corner yesterday.
Sergio Ramos added a third shortly after and Dani Carvajal rounded off the scoring seven minutes from time with a looping header to move Real back to within three points of La Liga leaders Atletico Madrid with four games remaining.
Ronaldo was starting his first league game for nearly a month due to knee and hamstring injuries as coach Carlo Ancelotti made six changes to the side that started Wednesday's 1-0 win over Bayern.
Gareth Bale was left out of the squad as he continues to recover from flu, whilst Xabi Alonso, Pepe and Karim Benzema were all rested.
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However, Ancelotti insisted all three of Ronaldo, Bale and Benzema would start on Tuesday.
"Bale had the flu before the game on Wednesday and was very weak for two days, so we thought it best to leave him out.
"He trained this morning, he is feeling better and, like Karim, he should be ready for Tuesday.