Mallorca end Athletic Bilbao's winning run
The Basque club had won their last four games to climb to fifth and Villarreal's 1-0 defeat at Deportivo La Coruna on Sunday had them dreaming of cutting the gap to four points and challenging for a place in next season's Champions League.
Instead, Cameroon striker Pierre Webo netted the only goal at the Iberostar stadium when he tapped in Emilio Nsue's centre in the 11th minute.
Bilbao have 38 points from 23 matches, seven behind Villarreal and one ahead of Espanyol, who lost 1-0 at home to 10-man Real Madrid on Sunday.
Barcelona, who drew 1-1 at Sporting Gijon on Saturday, lead the standings with 62 points to Real's 57.