Los Blancos earned a hard-fought victory on Monday night, with the attacking pair finding the goals to get their Liga campaign back to winning ways
They may have been delayed nearly 24 hours after floodlight cables were sabotaged on Sunday night, but the game was worth the wait for Madrid, with Benzema's 13th minute strike and a Ronaldo penalty late on sealing the win.
Michael Essien and Luka Modric got the nod ahead of German midfield duo Sami Khedira and Mesut Ozil, and that selection was justified as Madrid made the perfect start.
A sweeping move saw Angel Di Maria cross for Benzema and the Frenchman clinically dispatched his effort into the back of the net to make it 1-0 to the visitors.
Jose Mourinho’s side came into the game on the back of a three-match losing streak away from home in all competitions, having already lost as many games as they did in the whole of last season.
And they had to survive a scare on the half-hour mark, when Iker Casillas did well to stop Andrija Delibasic’s header, before Mikel Labaka’s follow-up was cleared off the line by the chest of Xabi Alonso.
Rayo had lost their last eight matches against with Madrid, their last victory against Los Blancos arriving 15 years ago, and rallied after going close to an equaliser. As promised by coach Paco Jémez, the hosts’ approach was admirable, but they always looked in danger of being caught on the break.
And so it was Madrid who went closest before half-time, Benzema finding space in the position Ronaldo had vacated, before seeing his curled effort batted away by Ruben in the Vallecano goal.
Vallecano should have been level five minutes after the break, when Alvaro Arbeloa’s back-pass was sent straight to Delibasic inside the area, but he miscontrolled with only Casillas to beat.
Benzema nearly doubled Madrid’s lead on the hour, only to have his goal ruled out when he was stopped for an incorrect offside decision.
Madrid’s inability to control possession in midfield was highlighted by Alonso picking up a booking for a rugby tackle on Lass Bangoura after they once lost the ball in midfield.
Modric faded out of the game in the second-half and was replaced by Ozil with 25 minutes remaining, shortly after Jose Carlos shot narrowly over from outside the area.
Madrid won the corresponding fixture last season by a single goal, with Ronaldo´s wonderful back-heel settling a tight contest.
The Portuguese international was making his 47th consecutive La Liga appearance and doubled his side’s lead from the spot with 20 minutes remaining, after his attempted cross hit the arm of a sprawling Jordi Amat.
He should have put the game to bed a few minutes later, but somehow managed to hit the post with the goal gaping from six yards after substitute Gonzalo Higuain had squared.
But ultimately it proved nothing more than a slight embarrassment for Ronaldo, during what was an often nervy display from Mourinho’s men. A miserable night for Casado was complete when he was dismissed in stoppage time, picking up second booking after a needless foul on Ozil.
There remains plenty to work on for Mourinho, not least his side's tendency to needlessly give the ball away. After the points they have already dropped this season, however, the victory was all that mattered.