Two first half goals by Antoine Griezzmann and one from Imanol Agirretxe set the Basques on their way to victory, and Xabi Prieto rounded off the win when he netted shortly after the re-start.
Javi Guerra scored a late consolation goal for the visitors in the final stages of the game but it was little use to Miroslav Djukic's side, who were shattered by their opponents decisive finishing in a frantic 20-minute spell.
The hosts began the match asking all the questions. Griezzmann narrowly failed to connect with a Carlos Vela cross after just three minutes, while David Zurutuza later could not get on the end of a cross from Carlos Martinez from the byline.
Agirretxe had the first shot on target, sliding on the floor to shoot and take Dani Hernandez by surprise, but the ball was eventually scooped up by the goalkeeper.
Oscar almost gave Valladolid the lead against the run of play but failed to reach a cross from Antonio Rukavina by a few inches, and then Real Sociedad made their dominance count.
Vela sent in a free-kick which the Valladolid defence failed to clear properly. As the ball bounced up on the edge of the area Mikel Gonzalez created space for himself by softly heading the ball into his own path and then squaring it to Griezzmann, who shot into the bottom corner with his left foot to give the Basques the lead on 33 minutes
Six frenetic minutes followed, with both teams creating chances, before Agirretxe doubled the hosts' advantage with a superb goal. Vela flicked a cross towards the forward, who controlled the ball instantly with one touch and then curled his shot into the top corner.
If the game seemed to be slipping out of Valladolid's reach with the second goal, Griezzmann soon made things even harder for the visitors with a sublime finish a minute before half-time.
Zurutuza launched a long ball from just beyond his own penalty area up the field, which the Frenchman controlled in the air with his left foot, brought the ball onto his chest and then smashed it into the back of the net on the volley.
Prieto completed a superb interchange between himself, Griezzmann and Vela to bag the fourth goal on 48 minutes and things could have got even worse for Valladolid as the hosts raised their game.
Hernandez had to make two saves to keep out efforts by Agirretxe, while substitute Ruben Pardo rattled the crossbar from the edge of the area.
Manucho missed a glorious chance to give his side some hope on 60 minutes, but shot straight at the legs of Claudio Bravo when he was through on goal.
Javi Guerra did eventually get a goal back, slotting in from 10 yards out after a smart piece of skill and a cross from Oscar Ramos, but the afternoon will be remembered for the brilliance of Griezzmann.