The resulting corner presented Antonio Amaya with another chance, but the Betis man could only head over.
Neither side could conjure up another chance until the 66th minute when Benat found Joel Campbell inside the box, but the Costan Rican's close-range effort went wide.
Nono was the next to come close for the hosts when he unleashed a swerving effort from outside the box, but it bent away from goal at the last second to fly just wide.
Valladolid's chances took a turn for the worse with just over 10 minutes left as they were reduced to 10 men, Antonio Rukavina bringing down Benat for his second yellow card.
The best chance of the game came in the 83rd minute when Jorge Molina was found by Nono, but somehow put his effort over the crossbar.
Betis had a man of their own sent off in the third minute of stoppage time as Amaya was shown a second yellow to receive his marching orders.