1) A draw would have been a disaster for Liverpool and, for once, a cause for celebration for Manchester United. Until the 73rd minute, it looked like their dedication to being as irritating as possible might get them that point.

As we saw with Chelsea v Manchester City last week, that can count to the lowlier club’s advantage: the pressure of keeping up an undefeated run can weigh much heavier than the pressure of trying to be the side that ends it.

But then Liverpool seemed to remember that they are the new Liverpool, and that they knew how to win; and that this United are the modern United, and can be easily beaten.

Reality duly started behaving and delivered what turned out to be a comfortable Liverpool win. That’s 17 unbeaten at the top of the table and counting for them; a fifth defeat of the season and yet more time ebbing away for Jose Mourinho’s Manchester United.

2) United’s line-up threw up a few surprises, if indeed we are still capable of being surprised by Mourinho’s selections. Matteo Darmian was selected for only the fourth time this season, initially playing in a back three alongside Victor Lindelof and Eric Bailly, who only started after Chris Smalling picked up an injury in the warm-up.

Diogo Dalot and Ashley Young were the wing-backs selected in Mourinho’s 3-4-3, and the intention was seemingly to match Liverpool’s front three man-for-man, keep their full-backs occupied, and perhaps most crucially, to leave Klopp guessing as to their intentions.

It’s also worth bearing in mind that this is the very formation that Mourinho branded as ‘defensive’ when Antonio Conte used it in Chelsea’s title-winning 2016-17 campaign; how’s that for an indication of those intentions?

3) With Trent Alexander-Arnold, Joe Gomez and James Milner injured, Klopp turned to Nathaniel Clyne at right-back; and as much as a throw-back the defender now seems in this Liverpool side, even he wasn’t yet at Anfield the last time Liverpool beat Manchester United in the Premier League back in 2014.

That aside, the only other uncertain selections – as ever for this Liverpool side – were in central midfield, and on this occasion, it was Giorginio Wijnaldum, Fabinho and Naby Keita who got the nod.

For all that Liverpool fans hold Keita in high regard, this was the first ‘big’ game he has started since the win over Spurs in September (or, more generously, since he got injured early in the away game at Napoli, which he started): he had not started against Chelsea, Man City, Everton, PSG or in Tuesday’s win over Napoli.

Sure enough, too, it was Keita who was withdrawn for match-winner Xherdan Shaqiri in the 70th minute, meaning he has played for Liverpool 20 times this season but completed 90 minutes just thrice.

Klopp has a record of introducing his new signings to the side gradually, but after some impressive recent displays, Keita will be hoping to force his way into his manager’s thoughts somewhat more forcefully in the coming weeks.

4) It has been some years since Liverpool were a side that relied on successfully subjecting their opponents to an early-game blitz, but there was no doubting their early intentions in this game, which started in exactly the same manner as Tuesday’s win over Napoli had ended: with both sides playing as if it were under ‘next goal wins’ rules.

Predictably, it was the hosts that got the better of that state of affairs, with Roberto Firmino and Fabinho both going close, and Dejan Lovren having an effort cleared off the line by Ashley Young.

With Liverpool having failed to score in the league just twice in 2018, their opener seemed inevitable, and it came midway through the first half courtesy of Sadio Mane from a truly exceptional Fabinho ball over the top of a static United defence.

A lot was made of the Brazilian’s inability to break into Klopp’s side at the start of the season; that he got the nod for this game ahead of captain Jordan Henderson was a huge vote of confidence in the £44m midfielder, and the Liverpool boss will be delighted to see his decision vindicated by such a sumptuous pass.

We’re really starting to see the best bits of Fabinho now. Dominated the centre with ease, picked good forward passes and did his usual fishhook tackles with those absurdly long legs 👏🏼 — Sam Tighe (@stighefootball) December 16, 2018

5) That lead lasted just nine minutes, however, as United equalised through their second and final shot on target – the other being a tame Marcus Rashford effort during that end-to-end first ten minutes.

In recent years, Mourinho’s gameplan in big games has come to depend on hoping to force an error out of the opposition, and that’s precisely what they got in the 33rd minute. Romelu Lukaku put what should have been an entirely innocuous ball into the box, and Alisson was well-positioned for a comfortable take, but for whatever reason took his catch with all the grace of a collapsing ironing board, dropping the ball onto his own knee as a result. It rolled out to Jesse Lingard, who couldn’t miss.

Alisson diving slightly backwards there. Doesn’t get forward enough on it as that’s why his knee gets in the way. Poor goalkeeping. — David Preece (@davidpreece12) December 16, 2018

It would turn out to be pretty much the only bright spot in another miserable afternoon for United fans, but for a good 40 minutes, it was something to cling onto, albeit a very Mourinho goal to score in a very Mourinho performance; and it teed up 40 minutes of play that saw United very deliberately trying to frustrate Liverpool and largely succeeding.

6) It would be tempting to see Alisson’s blunder as hubris for a particular level of over-hype, given all the praise that has come his way over the past few months and particularly this week, when his injury time heroics kept Liverpool in the Champions League. That’s certainly how Twitter reacted.

This was not a player getting a deserved comeuppance, or who had been publicly hyping himself, but simply a goalkeeper who had been rightly praised for a number of match-winning performances.

But a barrage of effusive compliments will always rub people up the wrong way, however well-deserved, particularly coming from a group of fans as large and loud as Liverpool’s.

Having enjoyed over-enthusiastically lauding their goalkeeper over the past few days – and, more pertinently, having relished piling the misery onto Jordan Pickford for an equivalent blunder in the final moments of the Merseyside derby – they must now take it on the chin when rival fans indulge their schadenfreude with equal gusto.

People: we’re a strange bunch, aren’t we?

7) The nature of the goal won’t have helped, but the atmosphere and the run of play immediately changed from exciting and open to petulant and niggly: Lukaku was booked for a foul on Mane, and Firmino should likewise have been carded for a cynical push on Rashford.

If the open, frenetic spell favoured Liverpool, this kind of game surely favoured United. Even more than most managers, Klopp’s sides tend to be a reflection of the man himself, and just as the German can occasionally appear driven to madness when he gets frustrated, so too does his side’s recent track record in this fixture suggest they find it difficult to cope with being deliberately needled.

Sure enough, Liverpool briefly reverted to their ineffective bad habits of yesteryear, with Nathaniel Clyne, Lovren, Georginio Wijnaldum and Fabinho all Gerrarding hopeless long shots into the stands or David De Gea’s hands in the first 15 minutes after the restart.

Looking at the shots stats and the scoreline would probably lead someone who missed the game to conclude Liverpool had repeatedly torn United apart as easily as Manchester City did last month, but for a very large portion of the game, they looked desperate and disaffected.

Long shots from defenders = ball out of play (usually) = what United want. — Andrew Beasley (@BassTunedToRed) December 16, 2018

8) Who’s the square substitute that’s a goal machine with all the flicks? Shaq! You’re damn right.

There was one obvious substitution available to Klopp as he was forced to acknowledge that something had to change – and it proved no less effective for all that obviousness.

Xherdan Shaqiri came on for Naby Keita in the 70th minute, and by the 80th he had scored twice, with both goals owing a debt of gratitude to a teammate by the name of A. Deflection.

If you are going to smash hopeful shots at goal, there are few players you would rather have doing it than Shaqiri. That he backed himself to make something happen was made very clear from the way he shouted for seemingly better-placed teammates to leave it as he sprinted onto the ball for both goals: Clyne for the first, Salah for the second.

The Swiss has now scored five goals for Liverpool, and three of them have come off the bench. I wrote towards the start of the season that Daniel Sturridge was Klopp’s perfect plan B, but would very much like to revise that opinion now please.

9) If, like Mourinho, there are any United fans who consider those deflections fortuitous, then it should also be pointed out that the build-up to both of those goals simultaneously spoke highly of Liverpool and were utterly damning of United

Shaqiri’s introduction seemed to snap them out of their stupor, and suddenly they were themselves again. Andrew Robertson combined smartly with Mane down the left in the build-up to the first, and the latter skipped giddily past the useless over-committed tackle of Ander Herrera on the edge of the box before delivering the cross that ultimately pinballed its way to Shaqiri’s feet.

Mane gave Herrera the meanest stepover before that goal. Jeez. Had that Spaniard watching the goal from the floor. — Zito (@_Zeets) December 16, 2018

10) The second was the result of a swift and cutting counter-attack, with Lovren winning the ball in the Liverpool half from a carelessly casual Fellaini pass and starting a direct passing move that culminated in another deflected Shaqiri finish.

Liverpool’s passing was nice and crisp, but the most notable thing about that second goal was how easy the visitors made it for them after giving the ball away.

The only player who even attempted to close down a Liverpool player on the ball was Victor Lindelof, who came sprinting 30 yards out of the back four to try and cut off a pass to Shaqiri before having to immediately go running back when the goalscorer laid it off to Wijnaldum.

The Dutchman was then allowed to literally walk the ball into the opposition half, and nobody made any effort to win the ball even as it worked its way between Mane, Shaqiri and Firmino, all the way to the edge of the penalty box.

A reminder here that United were already 2-1 down at this point; they can hardly claim they were trying to simply camp out on the edge of their box to try and play out a draw.

Mourinho strongly rebuffed accusations of a lack of effort from his players after the game, but in defending his players he has only further condemned himself. If those were the instructions he gave his players, then they should feel deeply insulted by his lack of faith in them; and fans, likewise, are justified in feeling embarrassed to see their club shrink to the point of such routine timidity.

11) The immobility of United’s central midfielders has been a problem all season, particularly against City; so why on earth did Mourinho bring on Fellaini, of all people, to sit just ahead of Herrera and Nemanja Matic – the exact same midfield three that struggled so badly against City?

Getting things slightly wrong against talented opposition is one thing, but to specifically make a substitution that emulates a previous catastrophic error against a team of equivalent quality in a game of equivalent magnitude is something else altogether.

12) It also raises the question of why Paul Pogba was even on the bench to begin with: in what situation might Mourinho have considered deploying him if not when shifting from 3-4-3 to 4-2-3-1, as he did at half time?

Whichever side of the fence you sit on as regards the falling-out between Pogba and Mourinho, there is nothing to be gained from having him present in the matchday squad but refusing to use him even when the game is crying out for his specific talent set; unless, that is, your goal is to embarrass your most expensive player.

If only there were some indication as to whether Mourinho can be a very petty man who likes to prove a point, we could unravel this damnable mystery.

13) “We can still finish fourth. It’s not easy, but for sure we are going to finish in the top six like all the other historically top teams but the best we can get is the fourth position. Right now we need to look to fifth and probably later we can look to the fourth.”

It’s only realistic that Mourinho is now setting the expectations as low as he possibly can, but let’s keep in mind that United finished second last year. It’s not just that they are 19 points behind leaders Liverpool; it’s that they are within three points of five other teams, namely Wolves, Everton, West Ham, Watford and Bournemouth.

That is by no means the sextet that United should be part of, but there they are. Losing to undefeated Liverpool is no shame, but at this point, even ‘we need to look to fifth’ seems slightly optimistic.

14) The whole thing just feels like a big sad mess for United and their fans. It is very true that there are structural problems within the club, which has allowed complacency to seep in to every level. No club has a name too big to allow that: not Bayern Munich, not Real Madrid and not Manchester United.

Yet that does not mean that Mourinho is not at fault. It was already bizarre that it was he who was picked to solve the problems the similarly-defensive David Moyes and Louis Van Gaal had encountered and exacerbated, but the way Mourinho has dug his heels in and become a parody of himself over the last few months only makes his position even more untenable.

When Chelsea changed managers, they looked to the best tacticians Serie A had to offer. When Liverpool changed manager, they chose the hottest, most exciting free agent manager available. When Tottenham changed manager, they plucked the best up-and-comer in the Premier League. When Manchester City changed manager, they got Pep Guardiola, former leader of the best club side of a generation, if not all time.

When Manchester United changed manager, they picked a man who had been sacked by a rival after alienating everyone at the club, from the boardroom to the medical room to the dressing room. You can’t say they didn’t know what they were getting, and it is hard to feel sympathy now that history is repeating itself at their expense.

15) That’s enough on Mourinho for now. The bigger story – or at least, it should be the bigger story – is that Liverpool have claimed a first league win over United since 2014 to put themselves back at the top of the table.

This was not a vintage Liverpool performance, but their title push has not been built on the extravagant, blistering stuff of last year which produced big scores in both directions. They deserved to win and they won; that is sufficient, and if they can keep it up, that is what will sustain them as realistic challengers, if not champions.

16) For all of that, though, this game felt like a barometer more than a football match: an indication of where these two clubs are, and where they are likely to be headed as we lurch towards the second half of the season.

Liverpool are good, not in a way that makes them cool and exciting, but in a way that makes them find a way to win. And Manchester United are bad, not in a way that can be solved through hard work and the pulling up of sleeves, but in a way that requires them to throw everything they’ve been doing out and try to start again.

Do you think they have the right man for the job?

Steven Chicken is on Twitter