Luka Modric's opener was cancelled out by Sergio Canales but Dani Ceballos - formerly of Betis - found the back of the net with a late free kick to ease the pressure on Real's interim boss Santiago Solari.
Real Madrid now sit fourth in the standings - 10 points adrift of leaders Barcelona - while Betis are down to seventh position after a third game without a win in Spain's top flight.
Madrid started the game in a different formation with Solari instead opting for 3-5-2, but the visitors had the better of the opening stages and netted with the first effort of the match.
Betis were matching their more illustrious opponents as far as general play was concerned, but mistakes at the back were giving Madrid chances to double their advantage and Modric lashed over the bar from a similar position to his opening goal.
Giovani Lo Celso got Betis' first shot on goal in the 26th minute by dragging a tame effort wide from distance, but Madrid wasted a good opportunity at the other end when Vinicius Junior fired straight at Pau Lopez from 12 yards after good work from Benzema.
Canales fired marginally wide just before the break, but Betis reached half time without troubling Keylor Navas and the foundations had been laid for Madrid to control the second period.
However, Betis improved after the restart and quickly set about playing at a faster tempo, with Canales getting a long-range effort on target in the opening stages.
Vinicius Junior had a weak shot saved at the other end, but back came Betis as Andres Guardado directed a well-executed volley marginally wide of the post from 20 yards out.
The pressure from Betis continued, and at the midway point of the second half the home team had their equaliser - although it was not without drama as VAR was used by the referee.
The assistant had initially flagged for offside after Canales had poked the ball past Navas, but the video replay showed that the midfielder had been level when running onto Lo Celso's pass.
Betis quickly set about looking for a second goal, but for all their pressure during the closing quarter of the contest they were unable to force Navas into any work and were eventually made to pay at the other end.
Ceballos had been booed by the home supporters when being introduced as a substitute, but the midfielder responded in the best possible way by sending a 20-yard free kick into the bottom corner.
Betis attempted to find a second leveller, but Madrid comfortably held on to regain a spot in the Champions League places at the midway point of the campaign.
REAL BETIS (4-3-3): Lopez; Barragan, Mandi, Bartra, Francis (Tello 67'); Lo Celso, William Carvalho, Guardado (Boudebouz 85'), Joaquin, Sanabria (Moron 88'), Canales
REAL MADRID (3-5-2): Navas; Varane, Sergio Ramos, Nacho; Carvajal, Modric, Casemiro, Valverde (Diaz 82'), Reguilon (Ceballos 74'); Benzema (Gonzalez 46'), Vinicius Junior