Jurgen Klopp says it's coincidence that his two previous management jobs at Mainz and Dortmund lasted seven years each.
However, with Liverpool struggling on his seventh anniversary at Anfield, questions are being raised whether the German can continue to maintain his incredibly high standards into an eighth year and beyond.
Sportsmail takes a closer look at the problems Klopp is facing this season and how he can turn the Reds' fortunes around.
STRETCHING LOYALTY TO BREAKING POINT
Managers instinctively trust players who have brought them success.
Naturally Jurgen Klopp loves the team that has ended Liverpool's Premier League drought, been to three European finals and won a domestic cup double last season.
However, there is a time to let go. Sir Alex Ferguson wasn't sentimental when he ditched David Beckham, Roy Keane and Ruud van Nistelrooy after feeling they had outgrown their usefulness. Klopp hasn't yet shown the same ice in his veins.
The average age of Liverpool's team was three years older than Arsenal's during Sunday's 3-2 defeat.
Seven of the players Klopp used at the Emirates were in their thirties and given their output over the past five seasons, it's no wonder they are starting to look a little leggy.
Younger players have been signed like Nunez, Elliott and Carvalho while the experienced Sadio Mane was sold but there are too many in the squad who are either past their absolute best or haven't yet reached their potential rather than being at their peak.
Klopp has to take some responsibility. He talks up Thiago, Firmino, Matip, Henderson, guys who have won things for him.
But he's in danger of relying on too many of them for too long.
ENERGY LEVELS FLUCTUATING
Klopp looks well for 55 but it's virtually impossible to keep up his levels of intensity year after year.
He lives every moment on the training ground, in the dressing-room, during matches and even at press conferences.
He attempted a lengthy explanation of why it ended at Mainz and Dortmund when it did.
He says the continual selling of top players eventually wore him down which is 'completely different' to his current situation at Liverpool where he can compete to buy the best. That's presumably why he signed a new contract last season.
Yet seasoned Klopp-watchers think his engagement levels may have dropped slightly from admittedly super-charged amounts.
He speaks a little softer, he sighs maybe a little bit more. Perhaps it's an optical illusion but without the glasses, he's not quite the same force of nature when results go a little awry.
The manager himself isn't ducking the subject: 'We have all got older but I have no problem with energy.'
Going toe-to-toe with City for so long and fighting for four trophies last season might finally be taking its toll.
LESS FLEXIBILITY THAN GUARDIOLA
The two big beasts of their managerial generation have taken the Premier League to new heights. The thrilling title races between Manchester City and Liverpool and matches between them have been simply brilliant.
But where Guardiola has appeared to gain a slight edge is his willingness to change and adapt the City team dependent on the individuals he signs and picks.
Guardiola won the league last season without a recognised striker, having missed out on Harry Kane he played a series of false nines and the goal register hardly dipped.
Now he's got the best centre-forward in world football, Erling Haaland, the team has adapted again.
Haaland has scored 20 goals in 13 games and City haven't yet missed Raheem Sterling, Gabriel Jesus and Oleksandr Zinchenko.
Klopp hasn't found the formula yet to suit his new £85million goal-getter Darwin Nunez who plays off the last shoulder and is completely different to Firmino.
He's often stuck to a 4-3-3 with Nunez on the bench. Recently he's started the Uruguayan in a 4-2-3-1 but things haven't gelled, yet. Klopp has work to do on the training ground.
Likewise, when his defence starts leaking, with Virgil van Dijk and Trent Alexander-Arnold dipping below their usual standards, there hasn't been any desire to become more circumspect in Liverpool's style of play.
The team could be without Alexander-Arnold, Luis Diaz and Andy Robertson against City. Maybe the manager will have a rethink.
LOSING CONTROL OF THE TRANSFER COMMITTEE
Klopp insists he's always been just one cog in the wheel of transfer decisions at Liverpool but there is less evidence in recent windows that new recruits bear the hallmarks of a 'Klopp player'.
Going back to his earlier times, signings like Sadio Mane and Gini Wijnaldum were absolutely perfect for Klopp's high-octane blueprint.
Transfers were still collaborative, the analysts persuaded the manager that Mo Salah would be a good fit, but there seemed a pattern.
The exemplary record in the market has not been quite the same recently. Naby Keita hasn't justified his £52million fee and could leave for nothing at the end of the season.
Nunez impressed Liverpool's players when he faced them in the Champions League but isn't a natural for the Klopp way of playing. Liverpool haven't got the financial backing of a sovereign state and can't misuse £85million.
Nunez was meant to bring an X-factor but it's not happened so far.
'My imagination doesn't let me see where the spark is going to come from in the next few weeks,' said Liverpool's 'other' German Champions League winner, Didi Hamann.
CAN HE PULL OFF ANOTHER 'MIRACLE'?
Liverpool were 10th after Klopp's first game against Tottenham in 2015 – the same league position they find themselves in today.
Against all the odds, the inspirational manager somehow pushed his team into a European final in his debut season at Anfield, almost through his own force of nature.
He was criticised for leading a fans' appreciation after a draw against West Brom but it worked in bringing the players and supporters together.
In that time, he has exceeded expectations. Not just the haul of four major trophies but those times when Liverpool have had their backs against the wall – qualifying for the Champions League when they didn't have a fit senior centre-half.
As Chelsea, Manchester City and even Manchester United continue to spend more than ever, it is clearly becoming harder for Klopp to pull off more miracles.
He's tried not to be tetchy and present a united front but the cracks showed at Arsenal, with Henderson involved in a scuffle on the pitch and then looking displeased when Klopp substituted him.
At Dortmund, Klopp stepped away after seven years, using the word 'exhausted'.
He denies history is repeating itself at Anfield but after the welcome distraction of the Champions League this week, he needs a result against City on Sunday like never before.