The home side took a lead into the interval, however, following a strike from Nosa Igiebor after 36 minutes.
Villarreal improved in the second period, but they could not make the breakthrough with Betis holding on for a vital three points.
Read how it all unfolded in Sports Mole's minute-by-minute live commentary of the action below.
REAL BETIS XI: Sara; Chica, Paulao, Amaya, Didac; Lolo, Matilla, Nosa, Vadillo, Verdu; Molina.
VILLARREAL XI: Asenjo; Mario, Musacchio, Dorado, Jokic; Bruno, Trigueros; Cani, Aquino, Pereira; Uche