Manchester United on alert as Ronaldo warns Real Madrid: 'Sack Benitez or I am gone'
Insiders suggest Barcelona rout prompts Real star to tell team-mates that he won't play for manager
Twenty-four hours on, the mutinous murmurs had still to subside. So shattering was Real Madrid's thrashing at the hands of Barcelona's aesthetes that Cristiano Ronaldo, whose relationship with manager Rafael Benitez appeared frayed beyond repair, reputedly told team-mates in the Bernabeu dressing-room: "Either he goes, or I go."
One needs no detailed instruction in the habits of Florentino Perez, who has worked his way through 13 coaches in 15 years, to know which option the notoriously impatient club president is more likely to take.
But Perez is as much to blame as Benitez and it was at the 68-year-old billionaire who Real's restive supporters expressed their opprobrium, waving white placards in surrender after Luis Suarez's second goal set the seal on a night of unmitigated anguish.
No team set up by Benitez, conservative to his core, are conditioned to lose 4-0 at home.
Rather, it is Perez's insistence that he sends out a starting XI studded with more stars than some constellations, while Benitez is left looking like the hapless fall-guy when it all goes as hideously wrong as it did here.
Real's fans have grown sick of Perez's perpetual revolution and his myopic obsession with marquee names. They recognise that a dismal run yielding just one La Liga title in seven years could soon become eight, now Barca have carved out a six-point lead that they scarcely look like relinquishing.
In the immediate aftermath, Real's ruling junta sought to quell the insurrection as only they knew how, by playing club anthem Hala Madrid at deafening volume over the Bernabeu tannoy to drown out 80,000 piercing whistles of disdain.
The spectacle, however, was even more powerful than the sound. Everywhere you turned, Real fans were fluttering white signs or white handkerchiefs in a quintessentially Spanish display of displeasure.
They also cheered Andres Iniesta, an ageless inspiration for Barcelona, to the rafters when he was substituted with 12 minutes left.
The applause was carefully calculated: they had offered a similarly effusive reaction to Ronaldinho a decade earlier, when the Brazilian orchestrated a 3-0 Barca triumph at Real.
On both occasions, conspicuous shows of admiration for the hated Catalan enemy was designed to cause maximum embarrassment for Perez and his board.
The players' verdicts mirrored the feeling of unease. Luka Modric, who alongside Toni Kroos had delivered one of the worst holding midfield performances in El Clasico history, admitted: "I think we weren't on the pitch. When we are a team we are very good, but when we are not it is difficult."
Few conveyed this disunity as starkly as Ronaldo, who has never been so tepid in the all-white strip.
There were moments when he seemed as if he would rather still be on the sofa with Jonathan Ross, promoting the latest film about his life, than doing anything that might save Benitez's skin.
He has made no secret of his distaste for the Spaniard's containing tactics and delivered the type of listless turn that suggested he would lean on Perez to issue the P45 forms there and then.
The more fits of pique Ronaldo throws, the stronger the rumours that he will decamp to Paris St Germain or Manchester United become.
His behaviour is unfair on Benitez, who is guilty of nothing more than trying to fashion a team in his own image despite constant pressure from above.
The manager was explicitly asked whether he felt hamstrung by Perez's demands - naturally, he denied it - given that at least two of his actions here suggested as much.
Firstly, he brought on Isco to replace James Rodriguez, when the self-evident choice was to hook a dreadfully out-of-sorts Gareth Bale.
With each match, the sense mounts that Bale, Perez's £86m poster-child, must play at all costs, however fruitless his toil.
Secondly, Benitez betrayed his instincts by leaving out Casemiro - the one player he had credited with lending a balance to this Real team - in favour of the superstars. The ensuing mismatch, as Modric and Kroos laboured pitifully in trying to unsettle a dazzling Barca midfield of Iniesta, Ivan Rakitic and Sergio Busquets, was a glaring indictment of Perez's one-track philosophy.
If you wanted a reflection of Barcelona's effortless superiority, it came within three seconds of the kick-off, as Busquets befuddled Bale with the cutest little feint.
It would prove the cue for a crushing demolition.
Suarez teed off the rout by bending the ball into the far corner from Sergi Roberto's visionary pass before Neymar hared past Danilo with ease to squeeze a shot underneath Keylor Navas that doubled the lead.
The signature flourish belonged to Iniesta, feeding off some gorgeous interplay with Neymar and then rifling his strike hard and true beyond the hapless Navas.
It fell to Suarez, aptly, to complete this act of elegant destruction, as he clipped his finish over the Real goalkeeper's head.
In all of these captivating passages of play, one could be forgiven for not noticing the reintroduction of a certain Lionel Messi.
While Messi, sidelined with injury for the past two months, returned seamlessly to the fold, manager Luis Enrique was asked it would be difficult reintegrating him in the long term, when Suarez and Neymar have scored 20 of Barcelona's last 21 league goals.
"Problema de la hostia!" Enrique shot back.
Roughly translated, this meant a "very large problem", with a strong expletive thrown in.
How the suffering Benitez must covet the luxury of such difficulties. His next two games, a dead Champions League rubber against Shakhtar Donetsk and a domestic trip to Eibar, afford scant chance of atonement.
By then, the trigger-happy Perez could well have made the most pressing decision for him.
The fact that the heat is now directly on Perez sparked the speculation that he might move to sacrifice Benitez sooner rather than later.
However, Zinedine Zidane, the club's first choice to replace the coach, is understood not to be convinced by the idea of taking over in the middle of what looks like turning into a difficult season.