Barcelona lost their 100 percent LaLiga record as Rayo Vallecano held them to a 1-1 draw at Estadio de Vallecas.
Lamine Yamal put Barcelona ahead from the penalty spot five minutes before half-time in what was their third successive away game after opening wins at Mallorca and Levante.
But Rayo claimed a deserved share of the spoils midway through the second period after Fran Pérez had scored for the first time since joining from Valencia.
Barcelona owed their point to an outstanding performance from goalkeeper Joan García, who made several outstanding saves after being overlooked by Spain manager Luis de la Fuente this week.
The visitors began brightly on a pitch that was bare in patches, with Yamal blasting straight at Augusto Batalla and Raphina reaching a wayward back pass to pull an angled shot wide.
Rayo’s direct approach soon began to cause big problems for Barcelona. and the hosts had a gilt-edged chance to break the deadlock after 12 minutes.
Álvaro García delivered the perfect cross for Andrei Ratiu six yards out, but his namesake Joan spread himself superbly to pull off a stunning save.
Rayo’s play was full of intensity and Barcelona were fortunate to clear their lines at times.
Joan Garcia dived at the feet of Isi Palazón to stop the Rayo striker capitalising from a few yards out, and he also had to be alert to hold Luiz Felipe’s header under his crossbar.
Barcelona had their moments as Batalla smothered Dani Olmo’s low 30-yard free-kick and the breakthrough came five minutes before the break.
Yamal’s drive into the box was ended by Pep Chavarría making contact with the teenager’s thigh.
The penalty controversially could not be checked as VAR technology was not working and that led to a deep sense of injustice among Rayo fans, who responded by raising the decibel levels.
Yamal kept his calm by sending Batalla the wrong way from the penalty spot to claim his second goal of the season.
Palazon swivelled to send a Jorge de Frutos cross skywards, but Barcelona should have doubled their lead in the final moments of the first period.
Yamal found Jules Koundé on the overlap and, after Batalla had pushed out his stinging effort, Olmo fired over from six yards with the goal gaping.
Olmo was off target again after the restart and Rayo made the most of their reprieve to step it up again and threaten from every attack.
Rayo were rewarded after 67 minutes as Palazon swung over a deep corner, which travelled unchecked to Perez standing alone on the edge of the six-yard box.
Perez made delicious contact on the volley, and the ball flew past Garcia and crossed the line after striking the underside of the crossbar.
Barcelona sent on Marcus Rashford and Chelsea target Fermín López just after the hour mark, but Rayo were denied the lead when Palazon sent De Frutos clean through.
Garcia stood tall to win the one-on-one battle and saved brilliantly from Perez again with Sergio Camello making a hash of the rebound.
