Miroslav Djukic's side have 21 points from 14 games, one behind Malaga in fifth and Getafe in sixth who are tied on 22 points.
Wildly inconsistent Sevilla, who have beaten third-placed champions Real Madrid and fourth-placed Real Betis at home this season, left the Sanchez Pizjuan to whistles from the crowd and are 11th with 18 points.
Valladolid's German winger Patrick Ebert netted on a break away after only two minutes and midfielder Oscar squeezed a shot over Diego Lopez for the second in the 12th.
Sevilla struggled to react until visiting striker Manucho headed into his own net just after the re-start, but their fightback was hindered when Gary Medel was sent off.
The combative Chile midfielder picked up a second yellow card in the 64th minute and that helped Valladolid weather a tricky final few minutes when they came close to adding a third on the counter.
Real Valladolid had 36.9% of possession during the victory.
Real Valladolid had 17 shots, including seven on target.
Alberto Bueno made the biggest impact of any Real Valladolid substitute after coming on for Omar Ramos in the 84th minute, as he took two shots.
Dani Hernández stopped four shots.
Los Nervionenses managed to dominate the possession game, and maintained control of the ball for 63.1% of the match.
Sevilla's players linked up for 422 passes and 42 crosses in defeat.
The seven attempts by José Antonio Reyes were the most of any Sevilla player.
Hedwiges Maduro went off due to injury in the 50th minute and was replaced by Geoffrey Kondogbia.
Alberto Botía's 17 passes to Cala were the most of any Sevilla teammates during the match.