LaLiga leaders Barcelona's 125th anniversary celebrations were spoiled by Las Palmas who claimed a shock 2-1 victory on Saturday after Fabio Silva scored the winner to extend the hosts' winless league run to three games.
In a game dominated by Barca, who had 70% of possession and peppered the goal with almost 30 shots, it was Las Palmas who made their few chances count to claim a famous triumph.
Barca remain on 34 points and lead second-placed Real Madrid by four but their rivals now have two games in hand, while the victory moved Las Palmas up to 14th place on 15 points.
"I think when we don't score the goals, the team struggles a little bit and this is what we have to change," Barcelona coach Hansi Flick said.
"... if we don't score a goal, then maybe it's possible for us to keep a clean sheet. So we have to defend better as a team, not only the last four or the defensive players, but the whole team and we can do it better."
Las Palmas constantly found space in Barca's box in the opening stages of the first half at Estadi Olimpic Lluis Companys but could not find the breakthrough despite creating a couple of chances that led to some goalmouth action.
Barcelona also lost full back Alejandro Balde to injury in the first half, with the 21-year-old taken off on a golf cart.
The Catalans struggled to find a way past the Las Palmas defence although on the stroke of halftime Raphinha made a counter-attacking run but saw his shot come off the crossbar.
Las Palmas struck the opening goal early in the second half when a sublime passing move that started with goalkeeper Jasper Cillessen finished when another former Barca player Sandro Ramirez scored from the edge of the box.
RAPHINHA EQUALISER
However, second-half substitutions, including the introduction of newly-crowned Golden Boy Lamine Yamal, helped Barca dominate and they equalised just after the hour when Pedri found Raphinha in a pocket of space near the edge of the box.
The quick-footed Brazil winger turned and fired a low, left-foot shot past Cillessen to make it 1-1 for his ninth league goal of the season.
Las Palmas were not deterred, though, and took the lead once more when Wolverhampton Wanderers loanee Silva broke through the offside trap to latch onto a pass from Javi Munoz and pulled the trigger to beat keeper Inaki Pena.
The home side pushed to equalise again and Raphinha saw his free kick tipped over by Cillessen.
LaLiga top scorer Robert Lewandowski also had two opportunities to level late in added time but saw a glancing header go wide before his shot was blocked by the defence.
"I'm very happy, it's such a big win for us, we worked so hard and we suffered a lot. It's three important points," Las Palmas midfielder Alberto Moleiro said.
"We stayed very compact and we didn't leave a lot of space between the lines, that was the key. Up front, when we created chances, we made the most of them."
