Are they simply the best? We compare Liverpool to the Invincibles & Pep's Barca

It is hard to believe that there was a time in the recent past when travelling to Tottenham Hotspur held a modicum of uncertainty — and even anxiety — for Liverpool.

A mere 800 days or so have elapsed since their preparations for the fixture were hit by a full force gale at Melwood. The players could barely hear manager Jurgen Klopp's instructions. At least one of those now departed felt there had been insufficient time to consider how to cope with Harry Kane. The team lost 4-1.

Win at the Tottenham Hotspur Stadium on Saturday evening and Liverpool will take their tally after 21 games to 61 points: more points than any club in any of Europe's leading leagues have attained at the equivalent stage of a season.

Maintain the pace they are currently setting and Liverpool will finish the campaign with 110 points, smashing the English top-flight record set two seasons ago by Manchester City, in what is widely considered the greatest title campaign. Liverpool already have more points than the totals they collected in the entire 1998-99 or 2011-12 seasons. They have the highest number of goalscorers —16 — after 20 games of any side in Premier League history.

With the title's destination an increasing certainty, the debate is already migrating to where Klopp's side sit in the pantheon of all-time Premier League and football greats. If their campaign continues to its logical conclusion, it will certainly be hard to resist the notion that this is the greatest we have seen from one team in a single season.

They are on track to make The Invincibles of Arsenal look ordinary. Their tally after 21 games in 2003-04 was 49 points as they had drawn seven games. Arsene Wenger's side won the league twice in three years but by 2005 finished 12 points adrift and lost eight times.

The only modest aspect to Klopp's side is their goal difference, one of the many measures by which City smashed the records in 2018. Liverpool's is 'only' the 12th best in Premier League history at this stage, by virtue of them winning eight matches by one goal. Double that tally and Klopp will equal Manchester United's record for wins by one goal in a single season — set in 2012-13 when Sir Alex Ferguson's lifted the trophy for one last time.

Of course, the true test of greatness is longevity. The best teams of all time deliver impact, trophies — and then legacy. Ferguson's side won the Treble in 1999 and proceeded to collect the Premier League title three more times in the next four years. Though United do not feature on the table of most points amassed after 21 games, it was a more competitive league back then. Liverpool are dominating one featuring Arsenal, Chelsea and Tottenham all in transition, United in disarray and Pep Guardiola's City giving up the ghost.

Bob Paisley's Liverpool lifted the old First Division trophy six times in eight seasons while collecting three European Cups between 1975 and 1983. By any measure, Klopp has a distance to travel to eclipse that, too.

Mark Lawrenson, who collected the league title five times in six and a half years at Liverpool after Paisley signed him, believes some perspective is needed. 'I don't think I've ever known a manager who is as driven as Klopp,' he tells Sportsmail. 'But it's too early to begin describing them as among the greatest. They have to win again and again for that. Football's so uncertain. Even when we were winning, we knew we were capable of playing badly if we stopped to think how good we were.

'It's why our coach Ronnie Moran used to bring in the league winners' medals in a cardboard box and toss them out at us like they were nothing.' Liverpool fans do not need reminding that when it comes to the Premier League, the team have won nothing yet.

City have demonstrated the danger of reaching for superlatives too quickly. Less than a year ago, they were being described as the Premier League's all-time greatest. It has taken the departure of Vincent Kompany and injury to Aymeric Laporte to change everything. A prolonged period without, say, Virgil van Dijk and Sadio Mane, could similarly damage Liverpool. They were vulnerable without Van Dijk in their Club World Cup semi-final against Monterrey.

Retaining Klopp and preserving what he brings is the ultimate challenge, of course. Liverpool's success is built on the foundation stone of a superb player acquisition system, driven by Michael Edwards, Barry Hunter and Dave Fallows, in which the manager is not the sole architect. But no Premier League team have successfully maintained ascendancy at the top after a great charismatic leader has gone.

The league table of biggest points hauls across the course of five top-flight seasons — another way of assessing which clubs from these shores have been the greatest — is dominated by United under Ferguson, with Paisley's Liverpool also featuring. Evidence, it would seem, that repeated success requires the same individual at the helm.

That is applicable to Guardiola's Barcelona, the side who must surely best lay claim to have been Europe's greatest in the modern era. Twice securing 58 points from their first 21 games under Guardiola's leadership in the early years of the last decade, they won three titles and two Champions Leagues.

Where Liverpool differ from most new Premier League title winners, of course, is that they have already won the silverware which is the ultimate hallmark of greatness. Were this season to see them claim that Champions League again and run away with the title, their place in that pantheon would need to be re-assessed.

'That would be something else,' says Lawrenson. 'To go unbeaten all season, win the league by a record number of points and then retain the Champions League. That would be enough to make everybody consider them differently.'

Don't bet against it.