The visitors took the lead after just eight minutes when Riki danced through a number of Betis defenders before curling a fine shot into the top corner with his weaker right foot.
Riki almost doubled his side's advantage five minutes later when he cut inside before curling an effort towards the bottom corner, but this time Adrian was equal to it in the Betis goal.
The hosts almost found an equaliser just before the half-hour mark when Alvaro Vadillo made his way down the right before finding Joel Campbell on the edge of the box, but his strike flashed just past the post.
Riki had another chance to double his personal tally shortly afterwards, connecting with Bruno Gama's cross only to see his header well saved by Adrian.
They did finally find the equaliser just a minute later, however, as Molina picked the ball up wide and drove into the box before sliding his shot underneath the advancing Aranzubia.
Both sides pushed for a winner in an end-to-end finale to the match, but neither could find it as the spoils were shared.