Valencia had to settle for a 1-1 draw with Las Palmas in the first leg of their Copa del Rey quarter-final tie at the Mestalla.
Gary Neville's men were dealt a major blow after 38 minutes when Wilfried Zahibo beat his own goalkeeper to gift the visitors the lead.
Nevertheless, Paco Alcacer - who captained Valencia after Dani Parejo was stripped of the armband - levelled the scoring after the break to keep his side's chances alive.
The return is scheduled to take place at the Estadio Gran Canaria on January 27.
Elsewhere, Sevilla did enough to record a 2-0 win over minnows Mirandes at the Ramon Sanchez Pizjuan.
Steven N'Zonzi opened the scoring after 20 minutes following some good work from Daniel Carrico.
The hosts pushed hard for a second goal in the remainder of the game and eventually got what they wanted well into stoppage time, Vitolo finding the net after an assist from Michael Krohn-Dehli.
The return at the Estadio Municipal de Anduva takes place on Wednesday.