It was the away side that took the lead after 30 minutes, however, when Ruben Castro pounced on a loose ball before finishing from close range, before scoring his second moments later.
It got worse for Granada in the early stages of the second period when Dorlan Pabon converted following good work from Castro, but Granada did have a consolation late on when Carlos Aranda headed home from close range.
There was time for one more goal, however, with Angel Lopez adding gloss to the score in the latter stages with a cool finish on the counter.
Read how it all unfolded in Sports Mole's minute-by-minute live commentary of the action below.
GRANADA: Tono; Ortiz, Siqueira, Mainz, Lopez; Nolito, Rico, Santos, Brahimi; Torje, Aranda
BETIS: Adrian; Chica, Mario, Paulao, Martinez; Igiebor, Canas, Perez, Vadillo; Castro, Pabon