The Guinea international was substituted at half-time against Atletico Madrid but deserves to get the nod at Manchester United on Sunday

Jurgen Klopp could hardly have been clearer, or more defiant.

You tell me,” he said, spreading his arms wide. “If you would sign a midfielder, tell me a name. What do you want?”

That was back in August, the Liverpool boss defending the club’s decision not to sign a replacement for the recently-departed Gini Wijnaldum.

We’ve never said we don’t want to improve,” Klopp added. “But count our midfielders. Different profiles. Now tell me which player we need? What should the [new] player have?”

Klopp’s rationale was clear. Wijnaldum had gone, but in Fabinho, Jordan Henderson, Thiago Alcantara, James Milner, Naby Keita and Alex Oxlade-Chamberlain, and with Curtis Jones and Harvey Elliott emerging, he was adamant the Reds had enough numbers, and enough quality, to move forward.

Fair enough, you might say, but a little more than two months on from that press conference, Liverpool’s midfield puzzle is one which remains unsolved. Not a problem as such, just something to look at in the quest for perfection.

It feels more than a little harsh to pick holes in a team which is on a 21-game unbeaten run in all competitions. Not since 1989, during Kenny Dalglish’s first spell as manager, have Liverpool managed better.

They are second in the Premier League, top of their Champions League group with a 100 per cent record, and have scored at least three goals in each of their last eight away matches, most recently the thrilling win over Atletico Madrid at the Wanda Metropolitano.

Clearly, they are some team, and well in the frame to win big honours this season. Beat Manchester United at Old Trafford on Sunday - and they are the favourites with most bookmakers - and the Anfield garden will look very rosy indeed.

Yet the midfield question remains. What is Klopp’s preferred trio, and can they stay fit? Can the tried-and-trusted continue to deliver, and are the others, the youngsters and the rotation players, capable of stepping up on a regular basis? 

It is Keita, more than anyone, who has become the centre of the discussion. Plus ça change, you could say. Three years into his Reds career, few players create as much talk or provoke such strong feelings as the Guinea international. A misunderstood gem or an expensive flop? You pick your side and you stick to it, it seems.

We can blame Klopp for this week’s debate, in fairness. It was his decision to substitute Keita at half-time against Atletico Madrid, and it is not the first time the 26-year-old has been sacrificed early when Liverpool have been seeking to regain control of a big game.

Remember April, away to Real Madrid? Keita didn’t even last until the break then, replaced on 42 minutes with the Reds 2-0 down. 

“It was not about Naby,” Klopp said that night, and he repeated those sentiments on Tuesday evening.

“It is really important to me that nobody thinks we played the first half – or the second part of the first half – because of Naby,” he told his post-match press conference.

Fair enough, although perhaps Klopp’s most telling line was that Liverpool “just had to defend the right side a bit better”. That was the area Keita had patrolled in the first 45 minutes, the area in which he (and others, let’s be fair) had been exposed for both Atleti goals. 

So it wasn’t about Keita, but it kind of was. Liverpool needed Fabinho on the pitch, and Klopp preferred to keep Henderson and Milner on, believing they would offer greater stability, concentration and physicality.

It will be interesting to see what happens at Old Trafford this weekend, then. Will Keita keep his place or will Klopp shake things up again? And what will it say if he does?

Last season, Keita didn’t play another minute after that Real Madrid substitution. The circumstances this time were different but he could be forgiven for wondering why he was the one singled out again, especially since he had delivered Liverpool’s second goal against Atleti with a 25-yard volley, as pure a strike as you could ever wish to see.

In a way, that is Keita’s Liverpool career in a nutshell. One step forward, swiftly followed by a backwards one. Moments of genuine class and promise, and then a setback which makes you wonder if he will ever truly be the player Reds fans thought they were getting from Leipzig back in 2018.

He still retains huge support among Liverpool fans, and why wouldn’t he? He works as hard as anyone, his underlying numbers are good and when he plays well - as he did against Watford last weekend, or at Crystal Palace last season - the Reds look an even more dangerous and exciting side going forward.

The issue is one of consistency, both of selection and of performance. Klopp regularly talks about Keita’s quality and potential, but it is clear that he still trusts others, notably Milner and Henderson, more, especially in the difficult moments. 

He was right to point out that Atletico was Keita’s fifth game in 14 days, a significant workload for a player with a history of muscle injuries, but it is somewhat telling that a player signed for more than £52 million ($72m) - the third most expensive transfer in Liverpool history, don’t forget - has only once managed to play five consecutive matches for the club. And that was in his first season on Merseyside.

It would be bold, but not entirely surprising, if Klopp were to stick with Keita against United. He has never started at Old Trafford before, but he would surely relish the opportunity to answer some of the questions being asked in the wake of the Atletico game. It would be a significant show of faith from the manager, a confidence boost at just the right time.

Keita, don't forget, could do with a decent run of form for a different reason too. 

Much is being made of Mohamed Salah’s contract situation as he approaches the final 18 months of his current deal, but Keita, like Oxlade-Chamberlain, is in the same position. 

And unlike Salah, those two don’t have four years’ worth of world-class performances, or the attention of the world’s top clubs, to help them negotiate an extension.

With Liverpool linked with a number of up-and-coming midfielders - most notably Jude Bellingham and Florian Wirtz - Keita knows he is under pressure to show he can be part of Liverpool’s long-term future.

A big performance on Sunday would be an ideal place to start, then.

Over to you, Jurgen...