Gaizka Toquero got a first-half goal to give Athletic Bilbao a 1-0 victory at Racing Santander on Sunday and boost his team's hopes of playing in the Champions League next season.
The result kept Bilbao in sixth place, three points off fourth place, while almost certainly condemning Racing Santander to relegation.
Athletic, who trail Sporting Lisbon 2-1 ahead of their Europa League semi-final second leg in Spain on Thursday, are currently in a position that qualifies them for that competition again next season.
Racing are rock-bottom of La Liga, and with only four games left they are 11 points from safety and very close to losing their place in Spain's top flight that they have held since the 2000-01 season.
Also on Sunday, Real Sociedad and Villarreal shared the points in a 1-1 draw that almost guarantees saftey for both clubs.
Marcos Senna put Villarreal ahead in the first-half but Carlos Vela snatched an important equaliser with a spectacular overhead free-kick six minutes from time to put Sociedad on 40 points, nine ahead of Zaragoza and Sporting Gijon in the relegation zone.
Villarreal move to 37 points, only six points from safety but with four games remaining their destiny is firmly in their own hands.
Granada snatched an important 1-0 victory over Getafe with a goal from the Argentinian Franco Jara that also pushes them closer to safety.
The Andalusian team, in their first season back in the top division since 1976, are eight points clear of the relegation zone on 39 points.
On Saturday a Cristiano Ronaldo winner gave Real Madrid a 2-1 victory in Barcelona that gives 'los blancos' a seven-point advantage over Barca at the top of La Liga and edges them closer to their first title triumph in four seasons.