Liverpool's win at Chelsea epitomises resilience Jurgen Klopp has built into team
Liverpool manager Jurgen Klopp's celebrations at the final whistle at Stamford Bridge offered a window into the importance of victory in his 150th Premier League match in charge.
Klopp's impact on Liverpool in that period has been immense, culminating in making them European champions for the sixth time with victory over Tottenham in Madrid in June.
And yet Klopp's record in domestic affairs is also formidable, with his tally of 92 victories in that time span only bettered by Jose Mourinho, who won 105 of his first 150 Premier League games.
It did not quite bring the title last season, when Manchester City pipped them despite Liverpool losing only one league game - but renewed belief is surging through those supporters who celebrated with Klopp at the conclusion of the 2-1 win over Chelsea that gave the Reds maximum points from six games.
This is a record-breaking Liverpool side building the platform for what they and Klopp hope will be the return of the league title - their holy grail - after a 30-year wait.
Liverpool dug deep to win on Sunday and become the first team to take maximum points from their first six games in successive seasons.
They have now won their past 15 league matches, with only rivals City putting together a longer run in top-flight history, when they won 18 between August and December 2017.
Few title wins are pretty as a picture but these three points will be as pleasing to Klopp's eye as some of the goal-fests Liverpool have inflicted on opponents in his previous 149 games.
As Klopp rightly said: "You will never win at Chelsea without putting a proper shift in and we did that today.
"It is exceptional. What can I say? We have to keep going. It never looks as easy as it did for Manchester City against Watford but we have not had these games yet. We have had to work for it."
Klopp is usually animated but the body language in his technical area at Stamford Bridge was particularly telling, both during and after a game in which Liverpool were placed under greater stress than they have been for some time.
He was non-stop from the first whistle, and particularly when Chelsea threatened to wipe out their two-goal lead.
Klopp fist-pumped his chest in the direction of his players, exhorting greater effort. The German's shouts carried rows back into the stands. He danced up and down on the spot when possession was squandered. He engaged fourth official Kevin Friend and Chelsea counterpart Frank Lampard in lengthy discussion on more than one occasion.
And then, when the final whistle went, Klopp's ecstasy was clear as he went around each member of his staff and players before tapping his heart in front of Liverpool's joyous support congregated in a corner of the Shed End.
In the space of those 150 Premier League matches Klopp has had a transformative impact on Liverpool, fulfilling his initial mission to "turn doubters into believers" and then some.
Not many of the team from Klopp's opening game away to Spurs on 17 October 2015 remain. At Chelsea, James Milner and Adam Lallana were on the bench while Divock Origi is out injured.
No-one should underestimate the sheer brilliance and resilience of Manchester City, not only in responding to defeat at Norwich by thrashing Watford but also the manner in which they overhauled and then stayed ahead of Liverpool last season.
What is telling, however, is that Liverpool's Champions League win appears to have sharpened their appetite for success and trophies not sated it. The Premier League is now their avowed mission.
They have shown themselves capable of different types of victories and this was one of the less eye-catching variety, but equally precious and offering Klopp a look at another face of his team.
Liverpool were nowhere near their best but it is one of the great old adages of a Premier League title-winning season that the key to success is winning on exactly those occasions.
And, as a bonus, Liverpool are also capable of scoring different types of goals.
The flowing moves and individual brilliance from the likes of Mohamed Salah, Roberto Firmino and Sadio Mane are a familiar sight.
But Trent Alexander-Arnold's powerful strike and Firmino's header, both from free-kick routines, meant Liverpool have now scored 34 goals from set-pieces since the start of last season, seven more than any other team.
If Liverpool are not performing at their best, Klopp still demands intensity, courage, commitment - the other sorts of excellence and quality he has drilled into his side over 150 games.
Those qualities were required here. Liverpool delivered on Klopp's demands - and the Anfield juggernaut rolls on.