Barcelona squandered the chance to move level at the top of LaLiga after being held to a 1-1 draw by Rayo Vallecano, ending their push for a 10th consecutive away win.
The champions looked set for victory when 18-year-old Lamine Yamal won and converted a controversial penalty just before half-time, dispatched with calm authority despite protests from the home fans.
Technical issues between VAR and the referee meant the spot-kick decision could not be reviewed, leaving Rayo furious.
Joan Garcia had kept Barça ahead with a string of excellent saves, but defensive lapses proved costly. Fran Pérez equalised after being left unmarked from a corner, hammering his shot high into the net to reward the hosts’ persistence.
Rayo even thought they had won it late on when Sergio Camello struck in the 86th minute, only for the flag to deny them.
Barcelona pressed through Pedri and Dani Olmo but wasted good chances, and their defensive frailties kept Rayo in the contest until the final whistle.
The draw extends Barcelona’s unbeaten away record in Madrid under Hansi Flick, yet it feels more like two points dropped than one gained in the title race.