The home side had the lead on the stroke of the interval when Mesut Ozil finished from close range, but Betis were unlucky to enter the break behind.
Betis started brightly in the second period, but it was two for Madrid after 57 minutes when Karim Benzema coolly found the bottom corner.
The away side had one back late on from a Jorge Molina penalty, but Ozil wrapped up the points for Madrid late on.
Read how it all unfolded in Sports Mole's minute-by-minute live commentary of the action below.
REAL MADRID: Lopez; Nacho, Carvalho, Albiol, Marcelo; Modric, Ozil, Casemiro; Ronaldo, Benzema, Callejon
REAL BETIS: Adrian; Chiva, Paulao, Amaya, Martinez; Benat, Igiebor, Canas; Castro, Pabon, Campbell