Jamie Carragher: 'Klopp's reliance on world-class Mane shows Reds squad shortfall'
The most important signing during Jurgen Klopp's tenure as Liverpool manager? You could make a case for Mohamed Salah, Virgil van Dijk or Alisson, following the incremental improvement that has coincided with each of their arrivals, but I still maintain that the correct answer is Sadio Mane.
He was the first of the big signings under Klopp and it was his influence during that first full season for the manager in 2016-17, when he was the club's joint top-scorer in the Premier League, that ensured Liverpool got back into the Champions League.
That was a huge catalyst when you then look at the development of this team and, without taking that first massive step forward, you would have to question whether Liverpool would have had the resources or such pulling power to attract the players who followed.
At £32 million (€35m), Mane was also an absolute steal and the shrewdest piece of transfer work by Liverpool in their dealings with Southampton.
Mane came in relatively early and quietly during a summer transfer window in 2016 that then spiralled to the extent that Manchester United ultimately paid almost £90m to recruit Paul Pogba.
It is not simply the timing of Mane's arrival or value for money that makes him so important. It has been the consistency of performances, especially in the past 12 months, that means he genuinely now merits the description world-class.
So how do you define world-class? I judge it by thinking about a fantasy world starting XI and whether any given player would either get straight into the team or at least be in the best two or three in the world in their position.
As left-sided attackers, I would rate Mane, Raheem Sterling and Eden Hazard as currently the best, especially now that Cristiano Ronaldo has become more of a striker and with the struggles of Neymar since the World Cup.
I also think that Mane is Liverpool's first genuinely world-class winger since John Barnes and the club's best wide left player for almost 30 years.
That in itself is a big explanation for why Liverpool have never quite taken that final step in the Premier League.
Look at the teams who win the title, and they invariably have players who can cause damage from the wide areas and are capable of 20 goals a season.
I played with world-class players in almost every position at Liverpool, but never real world-class specialists in either the wide left or right areas.
That is not to diminish those who operated in those positions, but it was often not even their preferred role. It was a relative weakness in our team and I think the difference when we finished second to Manchester United in 2008-09. United, by contrast, had the options of both Ronaldo and Ryan Giggs.
Yet having watched Mane over the past four seasons, I believe he would have pushed us that extra step if he had been in that team of Steven Gerrard, Xabi Alonso and Fernando Torres.
We lost only two games that season - two fewer than United - but just could not get enough wins.
Mane's recent statistics underline his influence. Take out the penalties, and he was the Premier League's top scorer last season by a clear margin with 22 - three ahead of Salah and Sergio Aguero. He is also out on his own so far in this calendar year with 15 goals, and that's even if you include penalties.
The recent goals against Chelsea in the Uefa Super Cup and then Southampton three days later were spectacular but, as you so often notice with the best players, they also came at important moments in the match.
What I most love about Mane is his complete absence of ego and how he always puts the team first. That was really noticeable to me in how he reacted to the arrival of Salah in 2017, when he had already been at the club for a year.
Salah was suddenly the most exciting forward in the Premier League, scoring 44 goals in his first season, but there was never even the slightest sense that Mane was put out. He even moved position to accommodate Salah and allow him to be the main goal threat.
With Roberto Firmino also becoming so fundamental to Klopp's system of pressing from the front, I feel Mane's contribution is not as appreciated as it should be.
Which brings me to the concern that I now have. Mane has become so important that Klopp is reluctant to leave him out and let him have a rest.
He has played in 53 club games since the start of the 2018-19 season. Of all the forwards in the league, only Salah has played more than his 4,515 minutes.
Firmino is also in the top seven for minutes played, and all three of Liverpool's forwards have featured in 52 or more club games since the start of last season.
The only Manchester City forward to have done that is Sterling, but what this still does not take into account were the international demands this summer on Salah, Firmino and, particularly, Mane.
Liverpool's season did not finish until June and he was then away with Senegal in the Africa Cup of Nations, playing seven matches.
The last was the final on July 19 against Algeria and yet he was still involved in the first match of the Premier League season three weeks later against Norwich City. It was similar the summer before, when he played in the World Cup and was then away with Liverpool in the United States in the International Champions Cup.
In an ideal world, Mane would have been rested this season until after the first international break and not started until September. Klopp said after last week's win over Southampton that no footballer should play more than 50 matches a season, especially in what he called the 'intense positions', and he has the resources in midfield to address this concern. His use of Mane, however, already suggests that Liverpool's squad is not strong enough in the attacking positions.
Mane has said that tiredness is only mental and that he has never had a holiday longer than 20 days since joining Red Bull Salzburg in 2012.
I hope he is right, but you cannot keep defying your body and my worry is that there will be a drop-off without a rest. How Liverpool absorb either scenario could very well decide whether another Premier League challenge can be sustained. (© Daily Telegraph, London)