Cristiano Ronaldo played the first hour of the game Saturday and scored his side's first two goals, the second of which was a stunning diagonal shot into the corner of the net, before being substituted to ensure he is in shape for Tuesday, reports Xinhua.
Sergio Ramos scored Madrid's third with a header, while full back Dani Carvajal finished off the rout against a rival that is now a firm candidate for relegation.
Getafe climbed out of the bottom three with only their second win since November. Adrian Colunga scored the only goal of the game in the first half and Getafe hung on despite having striker Ciprian Marica sent off in the 36th minute of the game.
Getafe's win meant that Betis were mathematically condemned to relegation before their home game against Real Sociedad had even kicked off in an atmosphere of anger and frustration among the fans in the Benito Villamarin Stadium.
Given the atmosphere it was hardly surprising that the visitors took all three points thanks to a first half penalty from Carlos Vela.
In contrast to Betis, Rayo Vallecano assured they will be in the Primera Liga next season as they won 3-0 away to Granada.
Barcelona play away to Villarreal in what is certain to be an emotional game following Friday's death of former coach, Tito Villanova, while league leaders Atletico Madrid travel to Valencia Sunday.