Athletic Bilbao stopped the charge of high-flying Villarreal in a key battle of likely European contenders at the new Estadio San Mames.
Two quickfire goals a little after the half-hour mark were all Athletic needed as they edged a game of few chances 2-0.
Moreno Mikel Rico headed in the opener in the 33rd minute and two minutes later Aritz Aduriz fired in a second.
Villarreal's comeback hopes were hampered by a red card for Bruno Soriano moments before half-time.
The win moves Athletic up to sixth in the table, one point behind Villarreal who remain fourth.
In the night's other game, Celta Vigo squandered a series of chances and failed to climb away from the bottom three as they were beaten 1-0 by Levante at Estadio Balaidos.
A floodlight failure at the start of the second half delayed proceedings by about 20 minutes but it did not dim Celta's attack, who forged a number of scoring opportunities which were each wasted in turn.
Papakouli Diop then made Celta pay for their lack of a clinical finish when he snatched an 89th-minute winner to claim what had seemed an unlikely three points for the visitors.