Villarreal drew 1-1 in their opening LaLiga fixture of the season at Granada, and their first under new coach Fran Escriba.
Escriba was recently announced as the successor to Marcelino following the latter's surprise departure.
After seeing his side lose 2-1 at home to Monaco in their Champions League play-off earlier this week, he watched them squander a potential victory undermined by poor defending.
Villarreal took the lead in the 61st minute. A foul by Uche Agbo on Nicola Sansone presented a free-kick on the edge of the area, and Samuel Castillejo curled a superb left-footed effort inside the right-hand post and beyond goalkeeper Guillermo Ochoa.
Their advantage lasted just four minutes, however. The failure to clear a 65th-minute Granada corner gifted Ezequiel Ponce possession directly in front of goal, and he capitalised by scoring with a routine close-range finish.
Alexandre Pato, Villarreal's highest-profile summer signing, was given his league debut but could not add to the goal he scored against Monaco.