On Sunday, Liverpool face the only team to deny them victory in the Premier League this season.
Their 1-1 draw with Manchester United in October is the sole blemish on a historic record.
The Reds are 14 points clear at the top of the table, and they will extend that margin to at least 17 if they win their next three matches.
Their commanding lead and equally assured performances have led many - almost all those outside the club in fact - to declare the title race a foregone conclusion.
If that's the case, then the question is this: will Liverpool become just the second side in Premier League history to go a whole season unbeaten?
Their greatest rivals will be relishing the opportunity to scupper those hopes and, in the process, issue a timely reminder of their magnitude, just as they did back in April 2018, when they sensationally came from two goals down at the Etihad to keep Manchester City's champagne on ice.
Poll United supporters, and you may find that a similar upset this weekend would be even sweeter.
Reason for United to be hopeful?
The pre-match air of confidence about Ole Gunnar Solskjaer might seem somewhat justified in spite of the 27-point chasm between the two clubs.
That's because United's league record against the so-called 'big six' this season is mightily impressive.
They have taken 10 points from a possible 12 against the present top four and have also beaten Spurs, making their New Year's Day defeat against Arsenal stand out as an anomaly.
They have found an immensely effective, albeit apparently simplistic, way of approaching these fixtures, sitting back and absorbing pressure before mounting rapid, clinical counter-attacks.
The injury to top-scorer Marcus Rashford is no doubt a significant blow, but the core gameplan is likely to remain the same.
United's recent form in this fixture is also strong even with the sides on opposing trajectories.
In fact, since Jurgen Klopp took charge in October 2015, he has only scored one domestic victory over his team's archrivals.
Might that point to the Red Devils holding a slight psychological edge?
Liverpool dictate the game's course
This has become, to some degree, a fixture of paradoxes. Even though it is United scrapping for points in their bid for a top-four finish sorely needed to offset their financial drift, it seems as if the pressure is on runaway leaders Liverpool.
But all season, the Reds have been dismissing the narratives put forth as potential obstacles. They have survived a serious injury to one of their most important players and come through the season's most punishing period unscathed, even emboldened, despite the lack of summer investment in squad depth.
And they know that in this fixture, their fate is almost entirely in their own hands.
Solskjaer was credited for a near-tactical masterclass in the autumn, but that disguises the reality: Liverpool were pretty close to dreadful by their almighty standards.
This time, if they stay patient, they should have enough to overwhelm the United rearguard, if not with the alarming ease of Manchester City.
No doubt the Reds will harness the power in Anfield in seeking to pummel the visitors into submission.
Moreover, their excellent defensive record in recent times - they have kept six consecutive clean sheets - suggests they will have an answer for the questions United ask.
Spurs were, for the most part, only allowed opportunities last time out because of lapses of concentration, and those are far less likely in the biggest fixture of them all.
And after all, Liverpool are up against deep defences and opportunistic counterattacks every other week when they face distinctly average opposition.
Let's be clear: United, who could be leapfrogged by newly-promoted Sheffield United this weekend, are themselves distinctively average.
The obvious counter here is the suggestion that derbies so frequently shred the logic upon which my arguments are based.
But they don't have to. If Liverpool truly rise to the occasion, they will win the game. United are merely waiting to pounce on any signs of weakness.
And that's the result of the present gulf in class, one which the leaders could brutally expose.
This doesn't have to be the only disappointment of 2019/20 for Liverpool. It can be one of the highlights.