Atletico Madrid suffered a shock 2-1 defeat to LaLiga newcomers Las Palmas at Gran Canaria Stadium on Friday night.
Diego Simeone's side came into the tie riding a six-game winning streak in the league and could have leapfrogged cross-town rivals Real, who had played a game more.
But the away side were undone by Garcia Pimienta's confident outfit who, if not for Girona would have been lauded as the surprise package of the young season in their first top-flight campaign in six years.
After a goalless first period the deadlock was finally broken 51 minutes into the game when Los Amarillos skipper Kirian Rodríguez arrowed a long drive past Jan Oblak.