From what we have seen, Liverpool will not budge on selling Philippe Coutinho, and that could well be one of the most meaningful decisions of this summer beyond Neymar’s move to Paris Saint-Germain - although it is of course connected to that.

This could have big repercussions for the English league, the Spanish league and the Champions League.

First of all, there are no two ways about it: Barca simply need a player like Coutinho, both tactically and for his quality. From a tactical point of view, I think he is a perfect fit.

Five players to replace Neymar at Barcelona Show all 5 1 /5 Five players to replace Neymar at Barcelona Five players to replace Neymar at Barcelona Ousmane Dembele (Borussia Dortmund) The Independent revealed on Tuesday that Dembele was at the top of Barcelona’s list of Neymar replacements. The 20-year-old looks like he is pushing for a transfer out of the German club after a training-ground bust-up with teammates further fuelled the rumours. He is a natural replacement for Neymar as a wideman with pace to burn and at five years his junior, he has bags of potential. Bongarts/Getty Images Five players to replace Neymar at Barcelona Paulo Dybala (Juventus) The other player revealed by The Independent to be top of the list of replacements is Dybala. The 23-year-old is one of the hottest young players on the planet and is tipped for a big future with the likes of Real Madrid and Manchester United also keeping tabs on him. However, Barca may use his relationship with Lionel Messi to persuade him to come to the Nou Camp. Dybala and his Argentine teammate are close friends off the pitch and often play video games together. Getty Images Five players to replace Neymar at Barcelona Philippe Coutinho (Liverpool) Coutinho has already been the subject of one rejected bid from Barca this summer and expect them to go back in for another one. The Brazilian has been part of the standard Barcelona trademarked recruitment campaign with current and ex-pros saying how suited he is to the Catalan club. The Independent has already revealed that Coutinho’s people are “70 per cent” sure that the move will go ahead once Neymar leaves. Liverpool FC via Getty Images Five players to replace Neymar at Barcelona Antoine Griezmann (Atletico Madrid) Catalan-based daily Sport revealed this week that Griezmann would be the man Barcelona will go for to replace Neymar. The Frenchman is a commercial goldmine as well as already being proven in La Liga as playing in a variety of attacking roles. His purchase would also weaken a rival but given the way he rejected Manchester United earlier in the summer, it would take a monumental offer to persuade him to leave. Bongarts/Getty Images Five players to replace Neymar at Barcelona Kylian Mbappe (Monaco) The 18-year-old is the best young player around, with it seeming last week that Real Madrid had beaten the likes of Arsenal and Liverpool to his signature. However, with £198m in the bank now, on top of the rest of their existing transfer budget, Barcelona could blow Real out of the water with another world-record move. To take a player of Mbappe’s quality from under the nose of their biggest rivals could only be seen as a good transfer window, even with Neymar’s exit. AFP/Getty Images

They have already lost Xavi while Andres Iniesta is already in the latter stages of his career so will play less, and they thereby don’t manage to control the ball in the middle of the pitch in the same way, or make it arrive for the forwards at the right pace. They have lost that.

Coutinho can offer this, he ticks all the boxes, and especially those penetrating passes. He has sometimes been called “a highlights player” but I think that’s wrong and unfair. Liverpool’s game last year was all about attackers alternating positions so much, and it was often down to Coutinho to choose the right tempo of the play. He is also probably a better positional player than a player on the break, as he gives the right angles for passing options, his body shape is good, and he always chooses the right option. The fact he can score from distance is also such an important quality, given how so many opposition sides set up against Barca and look to close the gaps while defending deep. It’s also worth noting that, having just turned 25, Coutinho has greatly increased his Premier League goal tally in the last three seasons - from five to eight to 13.

He’s so crucial to Liverpool’s timing and build-up play that, without him, they would have to change their game significantly. I don’t know if they will continue with the same approach as last season but they often had close to 60 per cent possession in games over the 2016-17 campaign, whereas against Watford and Hoffenheim this term it dropped a lot without him.

If they did lose Coutinho, I would expect their play to be much wider, especially having pace on both sides now with Mohamed Salah having joined Sadio Mane.

But, given what Liverpool have already rejected - a latest bid of £91m - they seem intent on keeping him. The question is whether Barca can offer enough to prise him away; to make it basic business sense for Liverpool to accept.

Doing that is arguably essential to the Catalans because they badly require both real first-team quality as well as strength in depth, and that was even before selling Neymar. The PSG striker formed part of what was arguably the greatest attack seen in decades so you can imagine the necessity now.

Barcelona actually need a centre-half, a central midfielder like Coutinho and another star forward - so, essentially, an entire spine of a team. And they just need that to compete with Real Madrid, let alone get back to what they were, such is the power of the repeat European champions’ squad. Real could well produce a dynasty, and have a historic impact on football in the way Barca did for most of the last decade, if Camp Nou does not take action. If they don't do what they need to do.

It is actually remarkable how it has got to this situation, when it was the complete reverse just five years ago - with Barca looking so superior - but not all that surprising from one perspective.

There is a theory I have been reading about called “the performance clock” that is so fascinating to coaching, football and all walks of life.

It is fundamentally the idea that once you start what is essentially a new project and then reach a certain stage of success - so, you could say, the revolution at Barca from 2003 to their dominance of 2011 - you get into a “secret formula” mentality; that you just have to keep doing what they did but without the same innovation.

It’s difficult not to think this has happened at Camp Nou of late, and is why they now find themselves in the situation they are.