Real Madrid's joy was shortlived when they had a first-half goal disallowed for offside
Barca's 1-0 win over Valencia earlier on Sunday has put them further in control of the title race.
Madrid had a goal ruled out by the video assistant referee because Karim Benzema's free-kick hit team-mate Antonio Rudiger's arm on the way in.
Both goalkeepers were busy, especially in the second half.
Betis goalkeeper Claudio Bravo, 39, made five saves including stops to deny Karim Benzema and Vinicius Jr.
Madrid's Thibaut Courtois made himself big to deny Juan Miranda in the second half and also stopped from Leicester loanee Ayoze Perez.
-- Courtesy of BBC Sport