An early goal from Gaizka Toquero sent Racing Santander one step closer to relegation while lifting Athletic Bilbao back into the European places thanks to a 1-0 victory.
Toquero got the only goal in the 12th minute to leave Racing 11 points from safety with four games left to go, while Athletic go up to sixth place.
The result was perhaps harsh on Racing who created plenty of chances but, in keeping with a record that has seen them score only nine goals in 18 home matches, they could not find a breakthrough.
Athletic snatched the lead with their first clear opening as Ander Herrera picked out Toquero who finished from close range.
Racing's Adrian Gonzalez saw his shot from the edge of the area charged down by Javi Martinez before Julian Luque launched a shot wide of the target.
Papa Kouly Diop's long-range effort was always rising but Racing kept the pressure on as they forced a series of corners.
Bilbao finally got off the back foot after the half-hour mark, but Markel Susaeta's close-range effort was smothered by Fernandez.
Fernandez was called on again at the start of the second half, keeping out Herrera's shot, but most of the action was at the other end.
Gorka Iraizoz could only parry Domingo Cisma's shot, but did better as he held on to Lautaro Acosta's effort on the follow-up.
Acosta then sent a header wide while Diop's shot from the edge of the area went over.
Fernando Llorente had a rare chance for Bilbao in the 70th minute, but Alvaro Gonzalez got in an important block.
There was one last chance for Racing in the 90th minute, but Iraizoz held on to Cisma's shot as the visitors escaped with three points.