Aleksandar Katai's second-half equaliser earned Alaves a 1-1 home draw which dented Sevilla's hopes of putting pressure on LaLiga's top two.
Jorge Sampaoli's side appeared to be on their way to victory courtesy of Wissam Ben Yedder's 16th goal of the season midway through the first half.
However, substitute Katai struck only his second of the season - both of which have come in the last three matches - 15 minutes from time.
It ended a frustrating night for the visitors who are now three points behind second-placed Real Madrid, who have played one match fewer and themselves are a point behind leaders Barcelona.
La Liga's third-placed team took a while to get into the game at the Mendizorrotza but, when their first genuine chance did come in the 23rd minute, Ben Yedder made no mistake as he drilled in a low left-footed shot.
The goal settled the visitors and they enjoyed the better of the play until midway through the second half when Alaves, having kept the deficit to just one, realised they could have a go.
Within 10 minutes of replacing Ibai Gomez, Katai had equalised from close range and the night could have ended even worse for Sevilla but Brazilian Deyverson's effort hit the crossbar.