Athletic Bilbao was unable to feed off its superb win over Barcelona in the Copa del Rey midweek, and was held to a scoreless draw by promoted Alaves in the Spanish league on Sunday.
Three days after beating Barcelona 2-1 despite playing the final minutes with nine men, Athletic failed to win again at home and stayed in seventh place in the league standings.
It was 11th-place Alaves that came closest to scoring at San Mames Stadium when Victor Camarasa struck the left post with a right-foot shot from outside the area in the 36th minute.
Athletic needs a draw against Barcelona at Camp Nou on Thursday to advance to the quarterfinals of the Copa del Rey.
Third-place Barcelona plays at fifth-place Villarreal later Sunday in the Spanish league to try to move within three points of Real Madrid, which routed Granada 5-0 at Santiago Bernabeu Stadium on Saturday. Sevilla moved to second by winning 4-0 at sixth-place Real Sociedad.
Madrid will have a game in hand after the end of this weekend's matches.