1) Imagine conceding first but establishing a 4-1 half-time lead. Imagine beating the side in fifth by four clear goals, and feeling as if it could have been more. Imagine boasting a nine-point lead and a 21-game unbeaten Premier League run. Imagine being quite so brilliant without ever being quite so brilliant.

Liverpool have been here before. Jurgen Klopp dismissed “bullsh*t stories” of the Reds being the only team in the last decade to top the Premier League table at Christmas without going on to win the title last week. Quite right, too: that was a different team, a different manager and a different set of players.

This is not quite the same. Brendan Rodgers’ 2013/14 side were excellent, but always felt like they were straining, playing at close to their maximum potential. Klopp’s team look as if they have more gears to shift through, that they have plenty left in the tank. They are playing at around 80%, yet are still cruising. It will take both a gargantuan f*ck-up from themselves and a sizeable effort from any of their stumbling challengers to topple them.

2) That first half in particular was a microcosm of this confusing Liverpool side. Fabinho, having conceded a chance through a terrible pass in midfield against Wolves, repeated the trick after ten minutes to let in Alex Iwobi. Sadio Mane followed suit shortly thereafter to provide Aaron Ramsey with an opportunity at goal. Arsenal had four first-half shots, and three came from sloppy Liverpool passes, with Ainsley Maitland-Niles’ opener the most costly.

Yet the hosts were as ruthless as they were lackadaisical. They equalised within three minutes of going behind, were ahead 90 seconds later, and 3-1 up 16 minutes after that. They smelled blood before there was even a wound, and were unrelenting in punishing any and every mistake. And there were plenty of those.

Liverpool are not averse to pointing a gun at their own feet. But they have insured themselves against catastrophe. If, in the unlikely event that the bulletproof Alisson and Virgil van Dijk cannot rescue them, they have more than enough firepower to inflict much greater wounds than any they might suffer.

3) Arsenal have a similar standard of forwards. Pierre-Emerick Aubameyang is a phenomenal finisher, Alexandre Lacazette is an excellent striker, there is no more naturally talented player than Mesut Ozil in the country, and Iwobi, Aaron Ramsey and Henrikh Mkhitaryan complement them brilliantly. The Gunners have scored more league goals than all but the current top three this season.

But their Champions League strikeforce is supported by a top-half midfield and a bottom three defence. Granit Xhaka and Lucas Torreira have been much-improved so far this season, with this defeat representing about five strides back after as many leaps forward. They will, given time and perhaps one more addition, only get better.

The same simply cannot be said for a defence that provided as much resistance as candyfloss in a tsunami. Unai Emery has the infrastructure of a squad to work with, but must have contemplated simply starting from scratch with his defence as he watched Roberto Firmino score his first two goals. January cannot come soon enough; not signing a new centre-half would be the sort of negligence Emery’s predecessor was known for.

4) It mattered not, but it was a shame to see Lacazette on the bench once more for a game of this calibre. Emery made four changes to the side that drew with Brighton, and was justified in trusting Iwobi. But Lacazette was far from the only party guilty of squandering chances in midweek.

The Frenchman had assisted goals in all three of Arsenal’s most recent league games; he offers more in terms of all-round play than Aubameyang, who had 13 touches all evening – six of which were kick-offs. It must have felt like a bad joke when the man he sorely needed to play alongside to support him was instead brought on in his place in the second half. Lacazette simply took up Aubameyang’s role of mannequin in Liverpool’s defensive drills.

Lacazette and Aubameyang have played 880 Premier League minutes together this season. In that time, they have scored 14 goals and assisted seven between them – that is a rate of one goal every 41.9 minutes. It might put pressure on Arsenal’s defence to start two strikers, but it would have put pressure on Liverpool’s too.

Lacazette has now started just six of a possible 14 Premier League games against Chelsea, Liverpool, both Manchester clubs and Tottenham. Arsenal have won one, drawn four and lost one of those games. If playing him means making too much of a sacrifice, that hardly seems to have been the case.

5) The first warning sign came within the opening minutes, when Bernd Leno was set upon by the Liverpool hounds. The German looked painfully uncomfortable under such pressure in possession, which only spurred the hosts on to push higher and harder. They sensed a weakness and would stop at nothing to exploit it.

It became a theme throughout, juxtaposed with the calm of Alisson. It might make for a harsh comparison, but the Brazilian’s passing accuracy (89.7%) was not only considerably higher than Leno’s (62.5%), it was also better than all but two of Arsenal’s starters.

When he played a fine ball into Firmino in the build-up to Liverpool’s fourth goal, the point was rammed home: these two sides both wanted to play out from the back, but only one had the foundations to do so. It was one of many things that emphasised just how wide the gulf is between a team and a manager writing its first few chapters, and one that has almost finished the book.

Look at this freakin pass from Alisson.https://t.co/EoQZScw7rf — A. (@KaizerT8) December 29, 2018

6) So obviously Arsenal scored first. And it obviously came from Liverpool passing the ball in defence. Dejan Lovren and Fabinho took it in turns to look up and pass it sideways before the former tired of their game and launched the ball forward. It was intercepted by Xhaka, capitalised upon by Iwobi and scored by Maitland-Niles, all in ten seconds.

Emery can take some measure of comfort in the fact that his biggest call did actually pay off. Maitland-Niles was one of precious few Arsenal players to emerge with credit after being trusted to man a flank typically dominated by Andy Robertson. He offered energy and purpose while the majority of his more experienced teammates were overwhelmed by both the occasion and the opponent. He should not be tainted by this humiliation.

7) It was the first time Liverpool had been behind in a Premier League game at Anfield in 2018; they were level within 112 seconds. Firmino’s no-look finish afforded him the opportunity to see whether Arsenal really had defended as badly as he thought they had as he tapped into an empty goal.

It started with the Brazilian carrying the ball forward from deep, which Arsenal seemed to have no counter to throughout. His first two goals came from a similar situation of a midfielder losing possession just beyond the halfway line – Xhaka for the first, Torreira for the second – before scampering back and pouring petrol on the dumpster fire that was Arsenal’s attempt at defending. Who thought Rob Holding would be such a big miss?

8) Salah deserves credit for his part in the first goal, which was reflective of his fine hold-up play throughout. The Egyptian is underrated when it comes to that side of his centre-forward role, with his comparatively slight frame hardly lending itself to bullying burly centre-halves. But he is clever in the way he gets his body in the way of the defender and the ball, drawing them out of position and exploiting the space left behind.

He received the ball with his back to goal at one point in the second half, pulling Sokratis away before picking out Fabinho’s run with a backheel flick. He inevitably got his goal from the penalty spot, but he has become a striker as selfless as he is ruthless: no-one created more than his two chances.

Salah making a fool out of Arsenal 😂 https://t.co/eOulnmqo3U — . (@VintageSalah) December 29, 2018

9) Paul Merson had it right. We all owe him an apology.

“Liverpool wouldn’t buy him tomorrow morning, I wouldn’t have thought any of the top four would,” he said of Torreira last week, to the protestations of Arsenal’s fervent fanbase.

“He could be playing at Southampton and wouldn’t get a mention, or Burnley. No one would mention it. It’s just that Arsenal needed it so badly.”

It was never intended as an insult – Merson said that the midfielder had done excellently thus far and was precisely what Arsenal needed. It was merely an observation that, as the right man in the right place at the right time, Torreira was put on an unnecessary pedestal. He has brought energy and fight to a midfield sorely lacking in both, but is not impervious.

As early as the sixth minute, Mane flummoxed the Uruguayuan with a simple turn. Then came the mistake for the second goal, tackled by the same player while dallying in possession. Arsenal’s defence was laughably bad, but they were hardly protected either.

It was a forgettable game during a poor run of form that he should recover from, and perhaps a timely reminder that he, much like this Arsenal side, are promising but far from the finished article.

He is still better than Eric Dier, mind.

10) Arsenal were 2-1 down, but most certainly not out. A team that invariably improves in the second half always has a chance of getting a result if they are within touching distance by half-time.

Then came Liverpool’s piece de resistance: a move that spanned Arsenal’s entire half, yet comprised of just three touches before it nestled into the goal. Robertson picked up the ball on the halfway line, played a delicious raking pass to find Salah in space on the left-hand side, his ball into the box was measured beautifully, and Mane’s finish topped it all off. Liverpool even make route one football look sexy.

Of course, it all came from an Arsenal mistake, with Sead Kolasinac’s needless pass back to Leno putting the keeper under immense pressure; he could only clear it out for a corner which only reached Robertson. It was Liverpool at their best, and Arsenal at their absolute worst.

11) Liverpool eased off considerably in the second half, as if to underline their new-found maturity and game management. Had they found themselves 4-1 up at home to anyone last season, they would have kept that same tempo and pushed for more goals, playing up to their role of the great entertainers.

Instead, they simply held Arsenal at arm’s length and conserved their energy. They had 57.8% possession in the first half, compared to 39.9% in the second.

In a way, that highlighted just how far ahead they are. They could have embarrassed Arsenal, but knew the job had already been accomplished in 45 minutes.

12) Liverpool did get a fifth just for good measure however, allowing Firmino to complete his hat-trick with a second-half penalty. The Brazilian had scored four Premier League goals in 1,433 minutes this season; he netted three in 90 on Saturday.

Klopp said that he was “close to crying” after seeing designated penalty-taker – and winner – Salah insist that Firmino take the spot kick. It was a timely show of unity that summed up a squad revelling in working together, but also a vital moment for a player who has been far from his best this season. Firmino’s is often a thankless task as the hard-working foil to Liverpool’s supreme attack, and he will inevitably be overshadowed at times. But his standards had dropped from excellent to average this season.

This performance will hopefully be a turning point for the most unique player in the Premier League. That Liverpool have been so good without him impressing is quite something.

13) The penalty compounded a quite miserable evening for Arsenal’s defenders. Lovren was pushed by Kolasinac in the area, having seen Sokratis swipe at Salah’s ankles to concede the first-half spot kick.

These are precisely the sort of mistakes that cannot simply be coached out of a player. A 30-year-old centre-half should not have to be taught how to tackle, nor should a 25-year-old left-back need lessons in how to jump without pushing someone. The 34-year-old Stephan Lichtsteiner was the game’s worst player and Shkodran Mustafi was substituted at half-time for a reason.

The first goal was the result of a defender kicking the ball against a defender. The second goal saw three players fall over themselves to try and block a shot. The third, while brilliant from Liverpool, exposed a lack of awareness, while the other two were avoidable penalties.

If Emery insists on using a system that places so much pressure on the defence, he ought to invest in it properly. Or purchase the rights to the Benny Hill theme. He’d get plenty of use out of it.

14) With that said, perspective is important. Arsenal are still fifth, two points behind the top four, and are in the preliminary stages of Emery’s tenure. He needs time, patience and money.

The 22-game unbeaten run was both the best and worst thing that could have happened. It showed that the new manager’s methods do work, that many of these players are more than good enough, and that Arsenal were not left too far behind their peers. But it increased expectations and led to restlessness at the first sign of familiar failings. They were too good too soon.

Emery took the reins at a side who had been controlled – not just managed – by one man for 22 years. He has to reverse the bad habits of a lifetime, and needs more than one window to mould this squad in his image. Rome was not built in a day, and a Wenger-less Arsenal was not built in seven months.

They have now lost three of their last five games. Emery might quietly be thankful that stratospheric expectations have come crashing back down to Earth. The sixth-best squad in England is currently fifth.

15) Mesut Ozil wasn’t the problem, was he?

16) As for Liverpool, they will not allow themselves to get carried away just yet. These supporters have had not only their fingers but their entire hands burned by the embers of belief before. For now, they will take each excellent result as it comes.

The calming influence of Klopp is much of what separates this side from their predecessors in 2014 and 2009. Brendan Rodgers embraced his role as the savior, the man who could finally deliver Liverpool’s title. Rafael Benitez did everything but, falling over himself in his attempts to suggest the Reds were up against it. Klopp has struck the perfect balance: he knows where Liverpool are, but also where they have been, how far they have come and how much further they need to go.

Take his first season for example, when Liverpool won two, drew one and lost two of their five Premier League games in December. In 2016/17 that became four wins, one draw and one defeat, before four wins and three draws in 2017/18. This season, it is seven wins from seven.

He has embraced the challenges of coaching in England, accepted the need to change so he can overcome them, and is all the better for it.

His management of this squad has been impeccable, with Liverpool looking so comfortable yet having so much more to give. The only element of this side performing to its absolute maximum is the defence; the midfield and attack can still improve.

Imagine that.

Matt Stead