Real Madrid reached the Copa del Rey quarter-finals but drew the second leg against lower league opposition for the second round in a row.
Real won the first leg 3-0 against second-tier Numancia, and made 10 changes for Wednesday's home meeting.
Lucas Vazquez put Madrid in front with a header, but Guillermo levelled from a counter-attack.
Vazquez scored a second from close range before Guillermo equalised again - this time with a header.
The minnows had Dani Calvo sent off late on for two bookings.
Real, who have not won the competition since 2014, also drew 2-2 in the second leg against Fuenlabrada of the third tier in the last round, having won the first game 2-0.
Atletico Madrid, Valencia, Alaves and Leganes are also in the last eight. Barcelona and Celta Vigo, who drew 1-1 in the first game, meet at the Nou Camp on Thursday (20:30 GMT).