A pair of goals from Karim Benzema and one by Marco Asensio, who was coming back from an 11-month injury layoff, were all Los Blancos needed to secure the three points as they played at their training base with the Santiago Bernabeu undergoing construction.
Madrid entered the day trailing Barcelona, who beat Leganes 2-0 on Tuesday, by five points in the table and saw a great early chance go begging when Eden Hazard was denied from close range after being played in on goal.
Valencia then had a Rodrigo goal ruled out just after the 20-minute mark after a VAR check overturned the strike for offside in the buildup.
The visitors continued to apply pressure and Geoffrey Kondogbia forced a fine save from Thibaut Courtois just before half-time with a piledriver of a shot from outside the area as the match remained goalless at the break.
Real would double their lead in the 75th minute when Asensio buried his shot from a Ferland Mendy cross with his first touch of the match after coming on as a substitute.
"We started well but after that Valencia grew into the game and we knew we had to change something and push higher up the pitch, that's what we did and we won the game," said Asensio, who had a dream return after expecting to miss the whole season before the campaign was interrupted by the COVID-19 pandemic.
"I feel a lot of emotion and satisfaction but there was a lot of work behind this goal but the most important thing is that we won and I'm here for the rest of the season."
Asensio then set up the third with a clever pass from a counter-attack that Benzema flicked over a defender before volleying home a golazo for his second of the game.
The result puts second-placed Madrid on 62 points, five behind leaders Barcelona, while Valencia remain in eighth place on 43 points.