Across their two games this season, the Red Devils' fiercest rivals have shown them exactly how far behind they are the true elite of English football right now.
If some thought the 5-0 shellacking from a Mohamed Salah-inspired Liverpool at Old Trafford in October was a shock aberration that manifested itself from the nether regions of Ole Gunnar Solskjaer's doomed reign as manager, then Tuesday's result at Anfield in the reverse fixture proved that it was anything but a one-off.
Once again, Salah was in freestyle mode, ending a seven-game scoring drought by registering his first goals in open play for over two months as Liverpool went top of the Premier League with a 4-0 victory.
The brace brought Salah's overall tally to 30 for the campaign and was his ninth in just six games against Liverpool's historic enemy. But if United thought the Egyptian was their main problem, they were sorely mistaken at Anfield on Tuesday evening.
This was every bit as dominant a performance as Old Trafford for Jurgen Klopp's men with Thiago Alcantara, in particular, turning in an outstanding display in the center of the park. Such was the Spaniard's peerless performance that it forced Paul Pogba into a hasty retreat inside the first 10 minutes. The France international went off injured with Gary Neville wondering on Sky Sports if that was to be his last-ever appearance for the club. No one in United's pale blue shirt could get near the former Barcelona and Bayern Munich star, who is in imperious form at just the right time.
So, 9-0 across two games for Liverpool against Manchester United in a fixture that is watched more than any other in world football. The harsh reality is, however, that those score lines are far from United's biggest issue against their fellow North West behemoth. Far from it.
Liverpool and Manchester United are currently on opposite ends of the spectrum
Liverpool, in stark contrast to United, are almost the textbook definition of how to run a modern-day super-club in the Premier League.
Their recruitment department leave no stone unturned to ensure that every player signed - regardless of transfer fee - improves the squad and you have to go back as far as 2016 to find a mistake in the market at Anfield, and the fee paid for Loris Karius was a relatively modest one of just over £4m.
United, on the other hand, throw money around like a sailor on leave when the window is open with little to no thought as to how certain players actually improve the squad. The £50m signing of Aaron Wan-Bissaka looks like one of the biggest and most abject decisions in years.
At a time when all the other top clubs in England were looking at developing a new attacking dimension from the full-back areas, that United signed Wan-Bissaka from Crystal Palace, a player who is far more adept as a defender than an attacker, shows up the scattergun and erratic thought process that exists deep within United's set-up.
United are in serious jeopardy of becoming an irrelevance; a wasting relic that survives by eating into its decades of stored-up nostalgia reserves. And as long as the thriving of the social media and commercial departments continue to cloud the judgment of the football operations at that club, however, Liverpool will remain their superior on the pitch.
So for all the hammerings handed out by Klopp's men this season, the thing that will hurt United the most is how much better Liverpool are run across every area of the football clubs. United must use them as their model going forward this summer, however much it pains them at Old Trafford.
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