Over the years, successive generations of Liverpool and Manchester United players have played out an almost unbroken series of appalling matches between England's most successful clubs. Naturally the question arises as to why this particular big-club rivalry is so uniquely awful in the world of football. It's not unknown for there to be good matches between Real Madrid and Barcelona, between the Milan sides, Boca and River . . . Why should Liverpool v Manchester United be so reliably terrible?

At some point, desperate for anything to take your mind off the game, the thought occurred that it might have something to do with the toxic atmosphere that surrounds it. Might the bad feeling spilling off the terraces be so malignant, the psychological pressure so intense, that the players become inhibited and lose the ability to play?

You only had to think about the theory for 30 seconds to know it was probably wrong: are the songs sung and the abuse shouted by Liverpool and United fans really any more poisonous than what you hear when Celtic play Rangers or Arsenal play Tottenham? Yesterday at least provided empirical evidence to back up that conclusion. The first behind-closed-doors match was just like the others, a sad anticlimax, dominated by fear and dread. It appears the teams by themselves are quite capable of generating all this without any help from the crowd.

Afterwards Ole Gunnar Solskjaer professed disappointment with a result that kept United top of the league, while Harry Maguire suggested United had demonstrated the progress they had made since their last visit to Anfield one year ago.

Sterile domination

In fact the game had showcased Liverpool’s decline. After a sharp opening quarter-hour, they gradually sank into a familiar pattern of sterile domination and in the end needed Alisson to bail them out. They’re now in their worst run of league form for almost four years, back in the days before Salah or Alisson or Van Dijk. Back then at least they knew they were a team on the up. Now they’re in a different phase: mature champions, who now look overripe, or at best distinctly autumnal.

This was the first time they had failed to score in three successive league games under Klopp. Scoring was never a problem before: what's gone wrong? Since it's the forwards who usually score, it's logical that scrutiny should fall on Roberto Firmino and Mohamed Salah. Certainly neither emerged with much credit from yesterday.

Firmino had five shots, more than any other player in the game, but hit the target with only one of them, a weak left-footer straight at De Gea. He has now failed to score in 14 out of 18 league matches, and has provided just three assists. Klopp has always defended Firmino, going so far as to suggest anyone who questions him does not understand football, but his contributions have lately grown so subtle as to approach Emperors’ New Clothes territory.

Salah had three shots and three misses. Just before Christmas he gave an interview to the Spanish sports paper AS, which featured the somewhat stagey reveal that he had supposedly been miffed to be passed over for the captaincy in a Champions League match in Midtjylland, with Jürgen Klopp giving the armband to the much younger Trent Alexander-Arnold. The interview sparked speculation that he might be lining up a summer move to Spain, but ever since Salah has been playing as though determined to quash all such speculation with his performances.

But Liverpool's attacking problems run deeper than a couple of misfiring forwards. The turning point came on October 17th, when Virgil van Dijk's knee crumpled under that challenge from Jordan Pickford. It might seem a strange moment to pinpoint – we're talking about Liverpool's attack not their defence. Why should the loss of their best central defender (and by Murphy's Law, their second-best and third-best central defenders) have sapped their goalscoring powers?

To understand why, just remember why Klopp was prepared to wait six months for van Dijk after his initial effort to sign him collapsed in a tapping-up scandal. It's because he understood that van Dijk was perfect for the system he wanted the team to play. Van Dijk offers the rare combination of recovery, pace and strength to defend against runners, and aerial power to cut out long counter-attacking passes that would give other defenders a problem. With van Dijk playing alongside Joe Gomez or Joel Matip, you can play one-on-one at the back.

High-tempo attacks

Without him, you have to be more cautious, and this is why Liverpool's system has started to break down. Even at their best in 2019 they were not a team that picked opponents apart, like the peak Barcelona or Manchester City sides. If those teams believed in quality over quantity, Liverpool's attitude was that quantity has a quality all of its own. Their strategy was to break teams down with relentless high-tempo attacks. They would put ball after ball into the opponent's box, always ready to risk losing possession because they were confident in their ability to defend the counter-attack.

Now Liverpool’s best ball-winning midfielders are playing in defence, while the midfielders playing in midfield and the full-backs are more conscious of the need to protect rather than to attack. They have become palpably reluctant to lose possession because they fear every counter-attack could be fatal. The result is careful finicky football that is too slow and predictable to surprise defences – slow aimless moves that meander from side to side before breaking down on the 27th pass.

Some Liverpool fans hope that Thiago’s elite playmaking skills can rediscover their lost creativity, but this is magical thinking. Thiago produced most of the flashes of individual quality in yesterday’s game (a recent arrival, he has maybe not yet grasped what Liverpool v United games are supposed to be all about). But he was also usually the player who lost the ball for United’s most dangerous counter-attacks. When so much play goes through one central node, it creates a point of vulnerability for the opponent to exploit.

Thiago can’t replace or restore the winning system that has crumbled without van Dijk. Liverpool were creative not because they had a magical individual capable of sprinkling genius on their attacking moves, they were creative because they could attack for most of the game with eight outfield players out of 10. Without defensive security, they’ll struggle to recapture their attacking abandon. But the most successful teams find they have the most impatient fans, so Firmino better have his hard hat handy.