Barcelona have suffered their first loss under new boss Quique Setién.
The defending La Liga champions were beaten 2-0 by Valencia, following an own goal from Jordi Alba and a strike from Maxi Gomez.
It’s their first defeat at the Mestalla Stadium since 2008.
Barca will lose top spot in the league if Real Madrid takes a point or more at Valladolid on Sunday.
Elsewhere, Sevilla beat Granada 2-0, Espanyol drew 1-1 with Athletic Bilbao and Villareal earned a 2-1 win at Alavés.
In the German Bundesliga, leaders RB Leipzig slumped to a shock 2-0 defeat by mid-table Eintracht Frankfurt, which ended their 13-match unbeaten run in all competitions.
Bayern Munich crushed fifth-placed Schalke 5-0 to close the gap on Leipzig to one point, while Borussia Moenchengladbach came from behind to beat Mainz 3-1.
In Italy’s Serie A, Atalanta forward Josip Ilicic scored a hat-trick, including a stunning free-kick from near the halfway line in his side’s 7-0 win over Torino.
Elsewhere, Genoa fullback Domenico Criscito missed a penalty for the first time in his career as the relegation-threatened team drew 0-0 at Fiorentina, while Bologna beat SPAL 3-1.