Los Beticos's Antonio Amaya picked up a red card in the 93rd minute, after Real Valladolid's Antonio Rukavina received one in the 75th.
Real Betis maintained control of the ball for 56% of the match.
Los Verdiblancos got off 15 shots, including four on target.
The six attempts by Jorge Molina were the most of any Real Betis player.
The combination of Rubén Pérez to Beñat was the most common during the match, as the two players connected 20 times.
Valladolid attempted just one shot, which was off target as their attack.