Carlos Vela helped Real Sociedad overcome a European hangover when he grabbed a second-half equalizer to earn a 1-1 draw against promoted Elche in La Liga on Saturday.
Valencia, expected to challenge Sociedad for a top-four finish next May, lost 3-1 to RCD Espanyol despite having taken an early lead though Helder Postiga.
In the late kickoff, promoted Villarreal came from behind again to claim a late 2-1 home win over Real Valladolid with a Giovani dos Santos penalty and a spectacular run and shot from Cani.
Sociedad impressed in their 2-0 Champions League playoff first-leg win over Olympique Lyonnais last week, but were second-best for much of the game against Elche.
Playing their first home game back in the top flight, the hosts took the lead after two minutes when a corner flashed across the area and Ferran Corominas stabbed the ball in.
Sociedad were lucky not to concede again and struggled to get into the game until Elche’s earlier efforts started to take their toll in the second half.
A cross from the right found Vela unmarked in the area after 74 minutes and the Mexico forward scuffed a shot inside the far post.
Former Arsenal striker Vela then curled a long-range effort against the crossbar near the end.
Sociedad will play their return match at home against Lyon on Wednesday.
Espanyol made a strong start against Valencia and had already missed three gilt-edged chances to score when, against the run of play, the visitors took the lead in the 10th minute.
Jonas set up the ball for Postiga and the Portugal striker, brought in to replace Tottenham Hotspur new boy Roberto Soldado, netted his first goal for the club.
Espanyol leveled when David Lopez nodded in a corner in the 32nd minute and Cristian Stuani put them in front with a header which flew in off the far post past a stationary Diego Alves two minutes into the second half.
With two minutes to go, French forward Thievy Bifouma thundered a shot into the top corner for Espanyol.