Barcelona can claim their 21st league title with a draw at Levante. Ronaldo has 36 league goals this season with two rounds left, five more than Barcelona forward Lionel Messi and two behind the record set by Telmo Zarra (1950-51) and Hugo Sanchez (1989-90).
"I am playing well," Ronaldo told Canal Plus television channel. "It''s true that I am fighting to be top scorer, but without obsessing about it.
"The team is playing well. The priority is to finish the season winning our last games. Our coach asked us to do so and that's what we are doing."
Ronaldo headed in Mesut Oezil's cross in the 24th minute, and the German midfielder found him again in the 58th for another goal.
Benzema scored two minutes after coming on in the 77th, before Ronaldo capped the win from the penalty spot in injury time.
Madrid coach Jose Mourinho had no mercy in the Spanish capital derby, deploying an attacking lineup that featured Ronaldo and Angel Di Maria flanking Gonzalo Higuain.
Goalkeeper Iker Casillas was rested, allowing backup Antonio Adan to start for Madrid. Madrid shone brightly from the start, controlling possession and easily breaching Getafe's area.
Marcelo, wearing the Madrid captain's armband for the first time, provided a constant threat from the left flank.
Ronaldo should have made more of a four-on-three counterattack in the 22nd, being tackled by a defender when a teammate was free. But two minutes later, the Portugal star rose above two defenders to head Oezil's curling cross past goalkeeper Oscar Ustari.
Getafe reacted through forward Adrian Colunga, who had his team's first shot on goal in the 35th and then came close with a powerful header that struck a defender's foot inside the six-yard box just before halftime.
Ronaldo added his second after Higuain had forced Ustari off his line, Oezil unselfishly laying off for the ex-Manchester United forward to rifle home.
Benzema latched on to Xabi Alonso's long pass before toeing the ball past Ustari for his 13th goal of the season.
Ronaldo then recorded his seventh goal in two games with a spot kick after Jose Ortiz had pulled him down in the area.
"(Ronaldo's) scoring numbers are incredible, but they are the result of a team effort," Madrid assistant coach Aitor Karanka said.