Athletic Bilbao's bid for a berth in next season's Europa League stuttered when they lost 2-1 at Espanyol on Monday.
The defeat meant Barcelona-based Espanyol, whose coach Mauricio Pochettino signed a two-year contract extension on Sunday, closed within three points of seventh-placed Bilbao with four games left in La Liga.
Sevilla and Atletico Madrid are fifth and sixth respectively on 52 points, Bilbao have 51 and Espanyol 48.
The teams finishing fifth, sixth and seventh qualify for the Europa League.
There was no change at the top as leaders Barcelona and second-placed Real Madrid lost on Saturday ahead of their Champions League semi-final second leg at the Nou Camp on Tuesday.
Barca, 2-0 up in the Champions League, have an eight-point lead over their arch rivals and are closing in on a third straight La Liga title.