Barcelona were stunned 2-1 at Deportivo La Coruna, opening the door for Real Madrid to reclaim top spot in La Liga later in the day.
Barcelona, coming off the greatest comeback in Champions League history with a 6-1 defeat of PSG on Wednesday, went down just before half-time on Sunday thanks to a Joselu strike.
Luis Suarez hit back immediately after the break, pouncing onto a poor clearance in the box and rifling past German Lux in the Deportivo goal.
But the home side proved resilient, and worked the winner on 74 minutes — Alex Bergantinos heading down and past Marc-Andre ter Stegen at the near post from a corner kick.
The loss keeps Barca on 60 points from 27 matches. Second-placed Real, who have 59 points from 25 games, will face Real Betis later on Sunday.
