Marcelo then struck over the Valladolid crossbar moments later with Madrid dominating the early possession but finding it hard to fashion clear-cut opportunities.
Rodriguez was heavily involved for Los Blancos and tried his luck in the 20th minute after being found in a dangerous position by Marcelo, with the Colombia international just missing the post from outside the box.
Benzema then headed a Dani Carvajal cross wide of the target with the two teams still level after a fairly laboured first 25 minutes of football in the Spanish capital.
Zidane's side really raised the tempo in the second half of the first period, though, with Rodriguez, Bale and Benzema all having decent opportunities as Valladolid had to ride their luck to stay level.
Benzema attempted to finish off an impressive Los Blancos move in the 38th minute, only for Jordi Masip to make a smart save before Bale tested the goalkeeper's reactions moments later.
Valladolid had to work extremely hard in the latter stages of the first half to keep the scores level, with Casemiro heading the home side's final chance of the opening 45 minutes over the crossbar.
Madrid also started the second period on the front foot - Benzema and Bale both having half-chances in the early stages as Valladolid settled into a defensive shape once again.
Rodriguez's return to the Madrid team lasted 57 minutes as he was replaced by Vinicius Junior with Zidane looking for more pace in the final third of the field.
Luka Jovic was the second player off the home side's bench 10 minutes later, with the summer signing from Eintracht Frankfurt joining Benzema in the final third of the field.
Jovic almost scored with his first touch from a Bale delivery; the crossbar came to Valladolid's rescue, though, as the visitors held onto their clean sheet entering the final 20 minutes.
Valladolid had a golden chance to make the breakthrough in the 80th minute when Nacho delivered a dangerous cross onto the foot of Guardiola, only for the striker to miss the post from close range.
Madrid finally made the breakthrough in the 82nd minute when Benzema turned on the edge of the penalty box before finding the bottom corner with a brilliant low strike.
Madrid, who were again without the injured Eden Hazard, will attempt to return to winning ways when they travel to Villarreal next Sunday, while Valladolid are next in action away to Levante one day earlier.
REAL MADRID (4-3-3): Courtois; Carvajal, Varane, Ramos, Marcelo; Kroos, Casemiro, Isco (Jovic 69'); James (Vinicius 57'), Benzema (Lucas 90'), Bale
REAL VALLADOLID (4-4-2): Masip; Moyano (Marin 59'), Kiko, Salisu, Nacho; Porro (Antonito 80'), Fede (Tuhami 84'), Michel, Plano; Unal, Guardiola