Andy Robertson and Jurgen Klopp ended up stationed very close to each other for much of the first half at Anfield. Perhaps they knew it was going to be a team effort.
A team effort to ensure that Liverpool's aggression remained controlled in the heat of this boiling pot of a fixture.
A team effort not to get too wound up by Manchester United's desire to slow things down at every opportunity, taking an age over one particular corner at the Kop end after 20 minutes.
And a team effort to eventually, unfathomably blow their rivals away with a record victory by seven goals to nil.
Seven.
But that goal-filled second half in front of the Kop was only possible because of what came in the first period, and the effort and aggression put in by the Liverpool players, in particular Robertson.
The Scot was pressed up on Antony every time the Brazilian got near the ball, always in his face and snarling away and ensuring that any attempt to build something from the eventually well-beaten visitors was quickly nipped in the bud.
After one particularly impressive challenge left Antony in a heap Robertson was there again, right in his face and helping him realise just what this fixture is all about. If he didn't know before, he sure does now.
Klopp was encouraging his defender too, although only in the periods when he wasn't lambasting referee Andy Madley following his failure to award a foul for an apparent arm in the face of Mo Salah from Lisandro Martinez.
Klopp fumed at that decision, particularly as the failure to award the foul resulted in United breaking away and almost taking the lead through a Bruno Fernandes header at the back post.
The Reds boss simply couldn't comprehend what had happened, and was still making his displeasure felt to Madley long after the incident.
In front of Anfield's Main Stand, Klopp was almost acting as a conductor of the crowd at one point, with his anger resulting in an increase in volume.
Eventually the Reds would break through when Robertson's superb ball caught out Diogo Dalot and Fred and allowed Cody Gakpo to burst in and score thrillingly. We weren't to know it at the time, but the floodgates had been opened.
A combination of performance and atmosphere seemingly overwhelmed United, and none more so than Fernandes who completely lost his head after 3-0.
The Portuguese was furious with the failure to be given a corner and then at what he saw as a foul on him from Alisson, at one stage seemingly forgetting the match was going on and chasing after Madley.
It had been a complete breakdown from a United side who came here so highly regarded and apparently ready to show that these tides had turned.
When Liverpool and Klopp are in this form, that couldn't be further from the truth.
