Barcelona coach Ernesto Valverde said the controversial penalty which earned Las Palmas a 1-1 draw on Thursday and gave Atletico Madrid hope in La Liga's title race had left "a bad taste".
Barca host Atletico 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.
Lionel Messi's brilliant free-kick looked set to restore their advantage to seven points ahead of this weekend's showdown at the Camp Nou but two decisions from referee Antonio Mateu helped lowly Las Palmas take a share of the spoils.
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.
"We do not know what happened in this play," Valverde said afterwards. "From the field I found it unspeakable, but these are things that happen."
Even after Calleri's equaliser, however, the visitors had 42 minutes to find a winner and, in truth, they created little.
The question now is whether three days is enough for Barcelona to recover, physically and mentally, before facing an Atletico team hunting their ninth win on the bounce.
"The match comes fast," Valverde said. "But that's how it is. There remains a bad taste, after not winning here when we thought we could have done."
Valverde had already 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 than Messi and Suarez in a two against one but the former's final pass to the latter was underhit and the first big chance of the game was lost.
Messi seemed determined to atone for his error and in the 21st minute he won a free-kick after another irrepressible run to the edge of the box. The Argentinian 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.
Any sense of injustice was then doubled three minutes after the break, 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.