Los Blancos came up against dogged opposition in the form of the Andalusians and claimed all three points courtesy of the Portuguese attacker's valuable double
Jorge Molina gave the home team the lead on 10 minutes before Gonzalo Higuain levelled 15 minutes later. Cristiano Ronaldo's strike just after the break then gave Los Blancos the lead, only for Jefferson Montero to equalise three minutes later. Ronaldo grabbed his second of the evening 17 minutes from time to earn his side an 11th straight Liga victory in Jose Mourinho's 100th match as coach of the Santiago Bernabeu side.
The home team made a bright start to the game yet it was still a surprise when they took the lead in the 10th minute. Nacho's chipped ball was brilliantly controlled by Ruben Castro before the former Deportivo man slid it into the path of the unmarked Jorge Molina, who expertly smashed the ball past Iker Casillas from 12 yards out.
Despite continuing to look dangerous in attack, Betis appeared shaky at the back and were punished on 25 minutes as Los Blancos drew level. Mesut Ozil's lofted pass found Gonzalo Higuain, who raced clear of Jose Dorado before slamming the ball past Fabricio from 15 yards, a superb finish from the Argentine who now has 20 goals this campaign.
Conceding an equaliser was an obvious blow for Pepe Mel's men yet they were able to recover their composure and came within a whisker of regaining the lead on 42 minutes. Salva Sevilla's free-kick from just outside the box looked to be heading in, only for Casillas to superbly tip the ball onto the crossbar before Madrid cleared the danger.
It could have been Madrid heading into the break with the lead though when the visitors tested the keeper just a minute later. Marcelo's chipped pass fell to Ronaldo, who had been played onside by Paulao, yet Fabricio was alert enough to divert the ball for a corner following the Portuguese attacker's effort from close range.
Betis started the second period impressively yet found themselves behind for the first time in the game on 52 minutes. Kaka's looping pass into the box was volleyed across the six-yard line by Marcelo with Ronaldo on cue to sweep the ball home - an instinctive finish from the prolific Portuguese.
However, the Verdiblancos found an equaliser only three minutes later with Madrid conceding from a set piece; an all too familiar event for Madridistas. Salva Sevilla's corner was not the best yet the ball rebounded off the chest of Alvaro Arbeloa and straight to Jefferson Montero, who smashed it into the bottom corner with Casillas completely helpless.
For all their hard work, Betis were to come away with nothing as Ronaldo's predatory instincts broke the hearts of the home faithful on 73 minutes. Kaka's corner was expertly headed towards goal by Sergio Ramos yet despite Fabricio's decent stop, the ball fell to the 27-year-old to half-volley into an empty net.
Madrid are back at the Santiago Bernabeu on Wednesday when they face CSKA Moscow in the Champions League for a place in the quarter-finals, while Betis are in action next weekend as they travel to Rayo Vallecano.
Barcelona can cut the gap at the top back to 10 points with victory at Racing Santander on Sunday.