The La Liga champions have picked up just two points from their past three games
Substitute Lionel Messi helps misfiring Barcelona salvage a point against Athletic Bilbao
The whistles and jeers started immediately after the final whistle at Camp Nou on Saturday, then Barca’s club anthem boomed forth, drowning out any dissent.
The Catalans had just drawn 1-1 with Athletic Bilbao, completing a week when they have picked up just two points from a possible nine.
It had almost been a second defeat in a row, after losing to Leganes on Wednesday, but Munir El Haddadi's late strike salvaged the draw.
There is no crisis yet, but losing at the bottom team and drawing two home matches is causing consternation in Catalonia.
Bilbao had been traditionally awful in Barcelona and had won only one of their six games all season
The Basques had not won away at Barca for 14 years and had conceded 40 goals and scored only six in that time.
Lionel Messi had been their scourge, yet he was rested for the first time this season, perhaps with a midweek Uefa Champions League game against Spurs in mind.
With five goals in his last five games against the Basques and 16 in his last 16 games in all competitions against them, he was missed, yet Athletic fully deserved their 40th minute lead.
When Oscar de Marcos fired home a cross from his captain Markel Susaeta at the back post, it vindicated their early excellence. And it should have been more.
Inaki Williams and Raul Garcia both went close with efforts in the opening 15 minutes.
Barca's fans remained impassive, largely concerned at how ordinary the Spanish champions had looked without Messi on the field.
Their defence has conceded eight goals in seven games, more goals than 11 other La Liga teams.
Captain Gerard Pique – Messi’s deputy Sergio Busquets was also on the bench - played De Marcos onside for the goal. It was the latest error from the defender.
Manager Ernesto Valverde did not bring Messi on at half time, but, with his side down against his former club, on 54 minutes, the substitute’s board with was raised in the sunshine.
The size of the roar gave an indication of the approval for the decision as Messi replaced Arturo Vidal, one of several close season signings who has so far failed to spark so far for their new club.
“We can’t just rely on Messi to come on and solve things,” said Luis Suarez after the match. “We should have won the game before he came on. That's why we are Barca.”
Even with Messi now on the pitch Barca huffed and puffed but could not find a way through.
Messi was unsurprisingly key to most attacking endeavours. He had a shot blocked and then a free-kick cleared off the line, while Suarez did have the ball in the net but it was disallowed for offside.
Philippe Coutinho hit the bar and then Messi struck the post as the tension grew and grew.
But, finally, with seven minutes to go Barca's patience paid off, with Messi integral to the equaliser. He
Coutinho shot over before Barça got their breakthrough after 83 minutes. Messi, of course, was involved, centring for substitute Munir to divert the ball home.
Two Athletic players punched in frustration on the same turf that Sami Kuffour had done in 1999 when Bayern Munich had lost to Manchester United in the Uefa Champions League final. The roar went up, the stadium came to life far more than it would if Barca were enjoying a routine victory.
There was still time for Messi to hit the post again to sum up a frustrating day for Barca.
It could have been worse, given they were seven minutes from losing, but they are clearly not firing on all cylinders as the last week as a whole has demonstrated.