Barcelona left the party early, their birthday also belonging to those who travelled the furthest to be there. There was music, candles and a cake, a piano, five presidents and Pep Guardiola singing on the screen, or lip-syncing at least, but by the time the club’s 125th-anniversary celebrations closed at the Liceu theatre on Friday night there were no first-team players. A little after half past nine, two hours into their grand gala on the Ramblas, a figure appeared in the shadow of the aisle and gestured to depart, 30 men in grey suits silently slipping out to prepare the final act, the crowning performance: in 14 hours they had a match to play.

There have been thousands of them since 1899 when Mr Kans Kamper [sic] put a 63-word classified in Los Deportes asking if anyone wanted to play foot-vall and 12 turned up. The day after the gala would be Barcelona’s 3,034th in La Liga alone, and the league hadn’t even started for another 40 years after their foundation; it was also supposed to be special, a finale for the festivities. Over 2,000 people had been at the Liceu, among them former players, managers and plenty of politicians, if not the mayor – he supports Espanyol – and on a sunny Saturday high above the city another 43,921 were coming to Montjuic to share the history, the moment.

It didn’t work out how they hoped, although it might have ended the way some suspected. In one part of the city, especially. At about the same time as Barça’s players had sneaked out the Liceu, a mile away their opponents, recently touched down at El Prat, were dining on the eighth floor of their hotel overlooking the port, a perfect plan coming together.

Las Palmas had come a long way – it’s 2,173km from Gran Canaria – and were familiar guests. The team who turned up for the first game broadcast in Catalan after the end of the dictatorship; visitors the night Josep Taradellas, in exile since 1939, first went to Camp Nou; opponents when Barcelona won their first Copa under the democracy, they had been there the day of the October 2017 referendum too, Spain flags stitched into their shirts. They hadn’t won any of those; this time, on Barcelona’s 125th birthday, they did. It was their first victory at Barcelona since 1971, and the first home defeat for Hansi Flick’s team all season. On this of all days.

As one paper put it – as every paper put it, in fact – Las Palmas had poured water on the party, which is at least better than pooping on it. Barcelona had suffered a hell of a hangover, said the front page of El Mundo Deportivo. “When you prepare a fiesta, it tends to end in a funeral,” reckoned AS; on their 100th birthday, Barcelona had been beaten too, by Atlético Madrid. And so it was: they had old shorts, white like the first day, a new anthem and a new mascot, designed by Carlos Grangel, but no win. Cat, who is a cat, got the first touch, taking the honorary kick-off. Two long exhausting hours later, Fabio González, born in Gran Canaria, got the last. Between those, goals from Sandro Ramírez and Fábio Silva had given Las Palmas a 2-1 lead and ultimately another win.

They had defended that lead tooth and nail until the ball fell at Fabio’s feet, the final whistle went, and subs and staff in yellow and blue ran on to the pitch – those that could still run, anyway. “I hurt everywhere but right now I don’t hurt at all,” the centre-back Álex Suárez said afterwards. Barcelona’s captain Raphinha, meanwhile, just sat on the turf, lost. One by one, his opponents came to help him to his feet but he shrugged them off, staring into space, not quite Lesley Gore but not so far off. He had scored but, he said later, he didn’t care. Asked to explain what had happened, he replied: “There is no explanation: we lost.” Why? “Because we played badly.” Another exchange ran: are you angry? “Yes.”

Well, of course. Barcelona had taken 27 shots and had hit the bar. Jasper Cillessen, who joked that he had got the inside track by watching Raphinha’s clips on Instagram, made a superb stop from the Brazilian’s free-kick. There had been missed chances and missed tackles too. A penalty shout or two. And yet this was no fluke, no freak result written off as luck and soon to be forgotten, Iñigo Martínez admitting “we didn’t feel right; it was hard for us to create, we lost the ball a lot” and Flick adding: “We haven’t had a really good match.” Worse, it was no one-off. Instead, this was the third consecutive league game Barcelona had failed to win, the advantage they built blown already.

Since they beat Real Madrid 4-0 in the clásico, Barcelona have only defeated Espanyol, 3-1 in the derby, and even that day Flick said he wasn’t happy, a three-goal first half giving way to a flat second. They then lost 1-0 to Real Sociedad, drew 2-2 at Celta Vigo, and now this. Eight points gone in three weeks. While the coach noted that they had key decisions go against them in all three matches, he was not handing responsibility to the refs and it is not about absentees either, although the four games that Barcelona have failed have been the four that Lamine Yamal has not started, and both Marc Casadó and Dani Olmo were unable to play here. In fact, curiously, this run has happened as players have returned, the squad no longer quite so short.

“What are you doing badly?” Raphinha was asked. “Many things,” he said, applying the full stop. And if some of it is temporary – “We had a great start, we have slowed a bit but I have no doubt we’ll come through this,” Martínez said – right now it is also real. Flick suggested that there has been a lack of cohesion and insisted: “We have to defend better.” They have to attack better too. Scoring the first goal changes everything, the coach said, but Martínez admitted “we’re struggling to create”. In Lamine’s absence, one of the front three has tended to be turned inside, instead of going for the throat. Robert Lewandowski looks his age again. The team that scored five against Villarreal and Sevilla, four against Girona and Madrid, 40 in 12 league games, plus four against Bayern, has three in three. The space into which they ran, identified now, is being closed; the space which they leave exposed, meanwhile, is exploited better.

The edge, the intensity has gone from their game, the press applied a fraction late. The offside trap, which was always a way of living on the edge but looked like genius, now looks risky again, the timing needing fine-tuning. Identified now, it surprises less and opponents’ movements are modified. Barcelona had caught the opposition offside 108 times until this run, averaging almost seven times a game. Kylian Mbappé fell into the trap eight times alone, Madrid 12. Real Sociedad, though, fell just three times, Celta two. Las Palmas were caught five times on Saturday, but not only did both goals come from invading the space behind Barcelona, two other clear chances were worked the same way.

And worked is the word, Martínez saying the bit that too often goes unsaid: that there is another team and they are good, the side who had not won in 23 games racking up their fifth win in seven since Diego Martínez took over. A side in which everyone contributes. You would name their outstanding players at Montjuïc, only you would have to name them all. That said, some of the definitions in the Canarian daily La Provincia were fun and not far off: Álex Suárez, the Tarzan of Tamaraceite. Scott McKenna, the banana Braveheart. Silva, the Robin Hood of glory. Javi Muñoz, doctor of physics and fury. Enzo Loiodice, the marquis of the Eiffel Tower.

“We knew Las Palmas could cause us problems; they could have scored more,” Martínez admitted. Watch the two goals again and they are wonderful, the ball taken from one end to the other, not by blind hoof but by design, one swift touch at a time, Barcelona drawn in and then defeated, space opened and occupied. “It’s mechanised: we practised that all week. We know that they have a high line that works for them but it was good for us,” Mika Mármol said. “We thought we could win, we really believed it,” José Campaña said, and so it was.

“The key was not to be small,” Alberto Moleiro said; instead, they were as huge as the effort they had made, the front of one Las Palmas paper declaring them “heroes”, another calling this “the great apotheosis of the century”, the “mother of all feats”. In the dressing room, music blared and players bounced about. Vicente Gómez, the former midfielder who was born on the island, played for them and works in the sporting directorate, was waiting. “He told me: ‘You don’t know what you have done,’” Suárez revealed. This is the 75th year since Club Deportivo Gran Canaria, Real Club Victoria, Atletico Club, Arenas Club and Marino Club de Futbol became la Unión Deportiva, an anniversary of their own: for the last 50 of them, they had been unable to beat Barcelona. Now, though, they had, more history made and another party starting.