Atletico Madrid slumped to their first La Liga home defeat of the season as they were beaten 2-0 by Espanyol at the Wanda Metropolitano Stadium.
Atletico boss left star striker Antoine Griezmann on the bench with one eye on the upcoming Europa League final against Marseille, while Diego Costa was suspended.
The visitors had won just one of their previous seven La Liga matches and appeared to be cruising towards the end of the campaign.
But they held Atletico at bay in the first half then grabbed a surprise lead eight minutes after the interval when Oscar Melendo's shot was deflected past his own keeper by Stefan Savic.
And Espanyol made sure of victory in the 77th minute when Leo Baptistao fired home from the edge of the area, leaving Atletico still with work to do to hold on to second place from city rivals Real.