Alvaro Vadillo caused problems for the away side early on, using his pace to get down the wing at every opportunity.
Neither side really dominated the opening stages, with the players feeling their way into the game in the opening 20 minutes.
The home side took the lead on 27 minutes through Antonio Amaya, who met a corner well and headed home to make it 1-0.
Ruben Castro almost doubled Betis's lead on 33 minutes, but his header went just wide of the post.
Four minutes later, Salva Sevilla came close for Betis with a strike from the edge of the area, but he couldn't get it on target.
Jorge Molina almost made it 2-0 on 51 minutes, but his shot from distance bounced off the bar and away.
A minute later, Alberto Bueno grabbed a surprise equaliser for the away side, firing past the goalkeeper with a powerful strike.
Betis regained the lead on 82 minutes when Joan Verdu collected the ball on the edge of the box and smashed it past the goalkeeper to make it 2-1.
Bueno then grabbed a dramatic late equaliser two minutes into injury time to bring the scores level.