Depor forward Riki galloped through to open the scoring in the seventh minute at Betis's Benito Villamarin stadium in Seville before Jorge Molina levelled for the home side four minutes after halftime.
The result left Betis in seventh on 49 points, four adrift of sixth-placed Valencia, while Depor are 17th, one above the relegation places.
The fifth and sixth-placed teams qualify automatically for the Europa League, Europe's second-tier club competition.
Betis last took part in continental competition in 2005-06 when they finished third in their Champions League group behind English sides Liverpool and Chelsea.
They are one of many Spanish clubs to have suffered severe financial problems after years of living beyond their means and were relegated in 2008-09 before winning promotion back to the top flight two years later.
Depor have fallen on hard times since their league triumph in 2000 and a thrilling run to the last four of the Champions League four years later.
The Galician club were relegated for the first time in two decades at the end of the 2010-11 season but came straight back up by winning the second division last term.