At around 10 to 10 local time on Tuesday Liverpool were leading Sevilla 3-0. The home side were pressing and had had chances in the first half but there was no real sense of danger. Only the knowledge of Liverpool’s past record suggested the game might not be over.

All they had to do was hold out, wait for the storm to pass, avoid doing anything stupid. Alberto Moreno did something stupid.

He committed a needless foul on Pablo Sarabia. Éver Banega took the free-kick, Moreno failed to track Wissam Ben Yedder and a fightback that might have been quashed with another 10 minutes of resilience was suddenly raging. It was Moreno then who miscontrolled and panicked to bring down Ben Yedder to concede the penalty that brought the second.

By half-past 10 it was 3-3.

There are two factors here, one to do with Moreno and one with the club as a whole. Moreno has had a decent season. He has changed his game, become more disciplined.

In a world in which the solution to any problem is just to spend more it is laudable that Jürgen Klopp has had faith and has tried to improve him. Coaching, after all, is what coaches ought to do.

But there is a reason Sevilla, having targeted Moreno in the Europa League final of 2016, targeted him again. There is a reason James Milner played at left-back for much of last season. If Moreno was not good enough then, it was a huge risk to believe he suddenly would be this season. This is not, though, just an issue of personnel.

It may be consoling to believe that one more acquisition will make everything all right but this is not just about Moreno, just as the defeat at Tottenham was not just about Dejan Lovren.

Liverpool’s system requires their full-backs to attack. The effectiveness of Mohamed Saleh and Sadio Mané is increased by having players overlap them as they cut inside. That is not especially unusual; it is how most elite sides play. But if both full-backs get forward, it means there needs to be some compensatory action to cover.

There has been talk in recent weeks, as Liverpool racked up four successive wins, scoring 13 times and conceding only once, that the full-backs have worked out a system so that only one pushes up at a time, operating in effect as pistons. Perhaps that can work, although it requires a complicated shuffling of the three defenders who remain.

But the bigger problem seems to be in the centre. Chelsea’s switch to a back three last season was an acknowledgment that they needed greater protection in the centre if their full-backs were going to push forward. Others have followed. There are exceptions but generally the modern adoption of the back three is a defensive move aimed at offering cover when the full-backs get forward.

At the very least there is need of a holding player (Chelsea, even with the third centre-back, often play two and away at Tottenham this season used three) to protect the two central defenders, to act as a breakwater and prevent opponents getting a run at the back line. That was something Klopp always had in his Borussia Dortmund days, whether it was an old-fashioned ball-winner, such as Sebastian Kehl or Sven Bender, or a more modern distributor in the manner of Ilkay Gündogan.

At Liverpool he has never had that. Jordan Henderson has many qualities: he has great energy and a willingness to sacrifice himself and he is a better passer than many seem to give him credit for. But he is not a natural holding player. Emre Can would seem a more natural fit for the role were it not for his chronic lack of pace.

Perhaps the logic has been that if Liverpool press well enough, if they remain compact enough, there is no need of a specialist in that role. That was a point Arrigo Sacchi made during his short spell as technical director at Real Madrid: for him the use of Claude Makelele was an admission of defeat but perhaps that is an easy argument to make for someone used to having players as gifted, responsible and positionally aware as Frank Rijkaard and Carlo Ancelotti in the centre of midfield.

There comes a point at which idealism must be placed to one side.

Liverpool have kept one clean sheet in 11 away games this season, which was in the 7-0 win at Maribor. They have let in three or more goals on four occasions this season and two in a further three games.

Flakiness breeds flakiness; as defenders lose confidence they become more prone to mistakes. A problem of tactics becomes one of culture.

Would signing a new left-back help? Probably. Do Liverpool need a proper anchor? Almost certainly. As time goes by, the £35m signing of Alex Oxlade-Chamberlain comes to seem increasingly baffling: there are a lot of problems at Liverpool but he does not seem the answer to any of them.

Moreno must take much of the blame for Tuesday but this is also an issue of structure, on and off the pitch.