A depleted Atleti were without Geoffrey Kondogbia, Marcos Llorente and Luis Suarez through suspension and an injury to Moussa Dembele compounded matters even further.
Still this didn't seem to hold the league leaders back as Yannick Carrasco followed up a smart supply from Angel Correa five minutes gone to prod home from close-range.
A deep delivery from Mario Hermoso eleven minutes later picked out Saul Niguez to take aim from the head at the back post, but had Claudio Bravo equal to the task.
Betis drew level after four minutes following a delightful volley from 10 yards out by Cristian Tello after an equally delightful delivery from Alex Moreno.
Atleti should've gone behind six minutes before halftime as a flick on from Aitor Ruibal landed perfectly to Emerson to profit, but instead the defender dragged wide.
The visitors then carved out a chance of their own seconds later when Carrasco fired against the side-netting from a move inside the six-yard area.
Diego Simeone's side lived dangerously ten minutes after the break when a header from Emerson following a corner-kick worked Jan Oblak to a point-blank save.
The pressure continued to mount a little later on the table-topping outfit, as a ball across the face of goal from Emerson left them off the hook.
Atleti could've fallen behind in the closing minutes from a low effort in the area by Tello, but Oblak got a strong hand to parry.
With time running out, Atleti should've sealed it from successive efforts by Correa but Bravo saved to deny the visitors the chance to extend their lead at the top of the table.