Lionel Messi's stunning free-kick was not enough for Barcelona as a controversial penalty earned Las Palmas a 1-1 draw on Thursday and threw La Liga's title race wide open.
Barcelona will host Atletico Madrid on Sunday, in a clash of first against second with extra weight, now that the Catalans' lead has been cut to just five points. Atletico thrashed Leganes 4-0 on Wednesday night.
Messi seemed to have set Barca on course to restoring their advantage to seven ahead of this weekend's showdown at the Camp Nou but two decisions from referee Antonio Mateu helped lowly Las Palmas snatch a point.
First, Mateu overlooked a handball from goalkeeper Leandro Chichizola outside the box, which could have drawn a red card, and then he awarded a penalty when the ball struck Lucas Digne on the arm. Former West Ham striker Jonathan Calleri made no mistake.
Barcelona will feel hard done by given Digne's handball looked entirely accidental, with Gerard Pique on the pitch after the final whistle venting his anger at the officials.
But even after Calleri's penalty they had 42 minutes to find a winner and, in truth, created little.
The question now is whether three days is enough for Ernesto Valverde's men to recover, physically and mentally, to face an Atletico team hunting their ninth win on the bounce.
Valverde had lamented the scheduling this week but Luis Suarez started, despite sitting one yellow card away from a suspension, which he successfully avoided.
It is hard to think of two better players to capitalise on a two against one but Messi's final pass to Suarez was underhit and the first big chance of the game was lost.
Messi seemed determined to atone for his error as he delightfully popped the ball over one defender, before driving past two more and winning a free-kick on the edge of the box. He took it, with the diving Chichizola having to push the ball around the post.
In the 21st minute, however, Messi repeated, winning another free-kick after another irrepressible run and this time it carried the more punitive result. Messi planted the ball left-footed into the top right-hand corner.
The first controversy came on the stroke of half-time as Chichizola came rushing out of his area but after skewing his clearance, the keeper quickly stopped the ball with his hand.
Mateu blew only for the interval, much to the anger of Valverde, who left the pitch while protesting to the official. Chichizola was fortunate not to be sent off.
Any sense of injustice was doubled three minutes after the break, however, when Mateu awarded Las Palmas their penalty.
Barca failed to clear a cross into their box and as the ball cannoned off the back post, it struck the oblivious Digne on the arm. Calleri coolly dispatched the spot-kick.
On came the extra firepower, as Philippe Coutinho and Ousmane Dembele replaced Aleix Vidal and Andres Iniesta but Barca rarely troubled Las Palmas in the latter stages. They must improve on Sunday.