Yes, he is 30 and isn’t the sort of signing that can transform a team for the best part of a decade like Virgil van Dijk or Alisson but, at £16.2million, Endo looks like one of the bargains of the summer in European football.

Honestly speaking, how many Liverpool fans could say they had heard of Endo before this summer? The answer is probably less than one or two per cent. Four or so months on, he is being serenaded by the Kop and talked about as a seismic loss in the next month.

Wataru Endo has been a revelation at Anfield since his £16m arrival from Stuttgart in the summer

Liverpool were left reeling after Chelsea sensationally beat them to the signings of Moises Caicedo (left) and Romeo Lavia (right) in the summer

Alexis Mac Allister can play the No 6 role and has timed his recovery from an impact injury on the knee perfectly, with Endo now jetting off to the Asia Cup. But the Japan captain will be sorely missed while he is away in the host city of… you guessed it – Qatar.

Japan always do well at the Asia Cup so Liverpool will not pencil in Endo’s return until mid-February at least, meaning he misses some crunch league games including a trip to Arsenal – they also play there in the FA Cup on Sunday – and the Carabao Cup semi-finals.

His departure has not made the headlines that Mohamed Salah’s exit to play for Egypt in the Africa Cup of Nations in the Ivory Coast, a move that has already been debated and dissected for months as a potential turning point in the title race.

But the void left behind by Endo – or ‘Leg-Endo’, presumably a play on ‘legend’, as he was called in Stuttgart – will be felt by Jurgen Klopp’s men. Of course, Klopp and transfer guru Jorg Schmadtke, plus FSG’s Mike Gordon are not surprised at all by Endo’s rise.

The manager’s phone was buzzing with text messages the day after Endo’s signing was first mooted, with former colleagues in Germany – from time at Mainz and Borussia Dortmund – singing his praises.

‘If it’s true, this is a genius strike, I have asked to sign him for years,’ said one message from a former Dortmund hero. Klopp told the Liverpool website that day: ‘It was a very positive thing in Germany – he’s super-highly respected. He is really happy to join us, which is nice as well.’

After another fine performance against Newcastle on Monday, Van Dijk said: ‘We know he has the ability to be playing at the highest level and he’s shown that the last couple of weeks. He’s made the next step and that goes with confidence – he’s a human being and confidence helps.

Virgin van Dijk (middle) hailed the talents of Endo and reckons the 30-year-old has made the ‘next step up’ in recent outings for the Reds

‘He’s a very solid six. And I think in modern-day football all the top teams have a very important six and it’s one of the most underrated roles on the pitch and you have to get someone there to protect and to also be the link to the front. He’s stepped up and we’re going to miss him.’

Glowing references from past and present, not that he needs them. His numbers do the talking. During his time in the Bundesliga, he ranked highest for most balls won in the defensive third (254), most aerial duels won (219), most clearances (175) and most headed clearances (105).

Klopp said recently that Endo has a trait that no one else in Liverpool’s midfield possesses, which is the simple – and sometimes lost – art of tackling. But he is much more than a midfield enforcer and Endo always looks to break lines with passes and is calm when pressured.

He is nicknamed the ‘Duel King’ in Japan for those stats and he has even written a book, Duel, and set up a video platform where he analyses his own performances and offers evaluation for young footballers. It also includes advice for parents.

There are many fascinating tangents in the book – Endo says Arsenal’s Takehiro Tomiyasu, a Japan team-mate, often gives up certain foods when he gets injured for superstitious reasons – but overall it shows his studious nature and analytical brain which has been crucial to Liverpool.

He is a growing voice in the dressing room and is always spotted encouraging team-mates in pre-match warm-ups or during games. And he also feels at home in Liverpool, especially noting his childhood love for The Beatles. His family, including four kids, recently joined him in England.

Jurgen Klopp revealed the deluge of messages he received following Endo’s signing that sung the Japanese skipper’s praises