Ronaldo made no mistake from 12 yards, on 16 and 38 minutes, after Martin Montoya had been penalised for fouling the Portuguese forward and then Karim Benzema.
Santi Mina brought Valencia back into it after the break before late strikes from Marcelo and Toni Kroos put a gloss on the scoreline to hand Real a morale-boosting victory.
Valencia are third in La Liga, just two points ahead of Real, while Zidane’s men have a game in hand.
Gareth Bale, Benzema and Ronaldo have not played much together this season but all three were involved in the opening goal.
Ronaldo embarked on a lightning-quick counter-attack after Bale had cleared a Valencia corner with his head and linked up with Benzema before being upended rashly by Montoya’s sliding lunge. Ronaldo dusted himself down and took the penalty himself, sending Neto the wrong way.
Valencia responded well to going behind and should have equalised just after the half-hour mark when Ezequiel Garay teed up Geoffrey Kondogbia inside the six-yard box. However, the Frenchman, who impressed in the first half, could not sort his feet out and bobbled a shot hopelessly into the arms of Keylor Navas.
Moments later, it was 2-0 and again Ronaldo was on the scoresheet from the penalty spot after Montoya had clumsily bundled Benzema to the floor. Ronaldo stepped up to the spot again and this time buried a decisive shot into the opposite corner to double his and Real’s tally.
The scoreline flattered the visitors somewhat and Valencia eventually made their breakthrough as Santi Mina ghosted beyond Nacho to head the ball beyond Keylor Navas from close-range following Dani Parejo’s pinpoint out-swinging corner. Navas was then forced into a wonderful stop to deny Parejo, flinging out a trailing leg to deny a goalbound effort from the Valencia captain.
Due to a defensive injury crisis, Francis Coquelin started in central defence for Valencia while top-scorer Simone Zaza was named on the bench.Zinedine Zidane was without the services of Sergio Ramos but was able to call upon Gareth Bale, Karim Benzema and Cristiano Ronaldo in attack.
Having withstood a flurry of Valencia chances, Real effectively sealed the win with six minutes of normal time remaining as Marcelo and substitute Marco Asensio combined on the left wing before the Brazilian jinked his way into the area and fired a low strike beyond his compatriot Neto at his near post.
Zinedine Zidane has vowed to turn things around at Real Madrid
With Valencia’s players looking exhausted and out of ideas, Real picked them off for their fourth goal in the 89th minute with Kroos scoring trademark goal from the edge of the box after being set-up by a delightful flick from Mateo Kovacic. In a week where Zidane’s position has been called into question, his players delivered the perfect response.
Real Madrid are in action against Levante next Saturday live on Sky Sports Football from 7.40pm while Valencia face a tough trip to the Wanda Metropolitano against Atletico Madrid on Sunday.