With hindsight, the first of many, many Manchester United mistakes came half an hour before kick-off.
As the pre-match playlist was making itself heard at Old Trafford, James' Sit Down - the adopted ode to Mohamed Salah - gave Liverpool supporters in the away end the chance to serenade their star man during his pre-match warm-up.
The schoolboy error fired up an emboldened away end and the world's best player was listening.
A little over an hour later, Salah had a hat-trick and Liverpool were 5-0 up.
The question now, then, is whether or not this wonderfully constructed and coached team are somehow even better than the one that won the Premier League title by 18 points in July 2020?
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Back then, there were few who quibbled at the suggestion that Liverpool were the best on the planet, but while that domestic success was earned through a teak-tough mentality and sheer force of will, this current side look more ruthless, more clinical, more in control.
Rarely did that 2019/20 vintage eviscerate teams in the manner they are doing almost weekly right now.
Liverpool have now rattled in 41 goals in just 13 games across all competitions this term, continuing their fine record of registering at least three in every away game.
Jurgen Klopp will not concern himself with such comparisons, but the Reds look just as imperious, even if there are more rivals to concern themselves with at the top.
They won't be concerning themselves with United, though.
On this evidence, the gap between the two sides is as yawning as it has ever been in Liverpool's favour in the Premier League era.
Ole Gunnar Solskjaer's expensively assembled patchwork quilt of a team are rudderless and the Norwegian is hugely out of his depth without an armband in sight.
Never was that more obvious than this as Klopp's side turned in a performance and a result that will live long, long in the memory.
Make no mistake, they will talk about this for years to come.
Liverpool had the lead inside five minutes when Salah released the immense Naby Keita who made no mistake against David de Gea.
It was a goal of such simplicity that the Reds probably couldn't believe their luck.
The amount of space Salah found himself in was negligent but it was not a rare defensive aberration for the hosts as Liverpool punished them moments later through Diogo Jota.
After a mix-up between Harry Maguire and Luke Shaw, Keita pressed and played in Trent Alexander-Arnold who delivered a low cross to both James Milner and Jota at the back post.
The third arrived via Salah as he converted Keita's low cross from the right with minimum fuss before he added another with a calm finish in first-half stoppage time.
The TV close-ups of the likes of Maguire, Paul Pogba and, most tellingly of all, Solskjaer, said it all.
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They were utterly shell shocked and appeared unable to believe what was unfolding during a first half that will compare favourably with any other from the Klopp era.
Salah had the match-ball just five minutes into the second half after a superb pass from the excellent Jordan Henderson put him clean through.
It was his 15th goal of the campaign and while he has some way to go to match that 44 haul of three years ago, the Liverpool No.11 appears hell-bent on giving it a good go.
If a picture tells a thousand words, the contrasting images of the two clubs' respective knights of the realm were enough to write several chapters.
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Sir Kenny Dalglish's beaming smile said it all about Liverpool, while Alex Ferguson's disgust, shock and bewilderment simply could not be hidden from view.
The sight of streams of United fans heading to the exit doors at half time laid bare just how horrendous the afternoon had been for the home faithful too.
It didn't get much better for those that stuck around, either.
Paul Pogba was given his marching orders around the hour mark for a horrible challenge on Keita who was forced to be stretchered off as a result.
It was cruel luck on the Guinea international after what had been a statement performance from him in the middle of the park.
The ECHO are celebrating Mohamed Salah's Liverpool Premier League goals from 1 to 100 with a special souvenir publication - and Reds fans can get a copy now!
For only £2.50 you will receive the 'Salah - Our Egyptian King' edition as well as a free glossy poster.
It is available in most supermarkets and newsagents across Merseyside and North Wales - or online by clicking here.
It was the sort of display that could yet prove to be a watershed moment for him at Anfield. An anxious wait on his latest injury now awaits, however.
"Can we play you every week?" roared the away fans as they soaked up one of their most enjoyable away days in decades.
You'll Never Walk Alone echoed around Old Trafford in the final minutes.
It had never sounded more triumphant. Certainly not here, at least.