A goal from Jeremy Mathieu after 44 minutes proved to be decisive for Valencia in their 1-0 win over Getafe before all eyes turned to the Ramon Sanchez Pizjuan Stadium.
Unfortunately for Valencia, Sociedad kept the heat on and returned to fourth place on goal difference with a 2-1 victory.
Ivan Rakitic gave the home side the lead after 10 minutes but his outing soon turned sour when he put through his own net six minutes later to level the scores.
Imanol Agirretxe’s strike midway through the half handed Sociedad the advantage and the hosts’ task was made even tougher when Jose Antonio Reyes was given his marching orders after half-time, leaving them no way back.
Elsewhere, Granada took a major step towards La Liga safety with a comfortable 3-0 win over relegation rivals Osasuna.
Youssef El-Arabi put them ahead with 23 minutes gone and though the home side had to survive some first-half pressure, they were given a helping hand when Nano saw red and conceded a penalty with 10 minutes to play.
Guilherme Siqueira stepped up and converted from the spot before Diego Buonanotte’s strike wrapped up a much-needed three-point haul.