The contrasts between Jurgen Klopp and Jose Mourinho may be clear, but if anyone shares commonalities with the Chelsea manager's current struggles, it is the German.
Liverpool's new boss will arrive at Stamford Bridge on Saturday with memories of how he too went from overseeing a team conditioned to win to one suddenly allergic to picking up maximum points.
Klopp's final season with Dortmund was nightmarish at the start, with the Bundesliga runners-up recording just two victories in their first 10 league games. Mourinho's defending champions, who swaggered through the previous campaign, have three wins from their opening 10 top-flight fixtures.
Klopp will recall the feeling of frustration his counterpart is enduring, and will understand why the Portuguese tactician recently admitted: "Chelsea's results are really poor at this time. I can't, and have no desire of hiding the truth. I'm struggling to come up with an explanation." In December, however, it was the Reds boss who was shrugging his shoulders as Dortmund continued to stumble: "I don't think I could ever have imagined things going as badly as they currently are for us."
There are, of course, differences between BVB's problems in 2014-15 and the ongoing concerns for the Blues. But there is a touch of irony that the strain of the 48-year-old's final term at the Westfalenstadion eventually led him to Liverpool, and to a fixture which could determine the future of an embattled Mourinho. In April, there was talk of the 'fighting football' enthusiast succeeding the mastermind from Lisbon. "The only thing I know is he's not coming to Chelsea," Mourinho said of Klopp. "He told me that personally, so I'm calm."
He may have been at ease back then, but after the club's shaky start to this season, Roman Abramovich will have certainly been window shopping. The troubles at Stamford Bridge seemed to speed up Liverpool's deposing of Brendan Rodgers and dart for Klopp. For one, the Reds would have been loath to compete with the Russian billionaire for a manager they've coveted since 2011, and there was also a belief that securing the German could help Liverpool capitalise on Chelsea's poor start.
As the man who proudly stated "you always want to be the team that can beat the one with more money," Klopp and the Blues were never an obvious match. The other part of Fenway Sports Group's thinking - whether Liverpool can compound Chelsea's woes - will be tested on Saturday. Their prepartions for the match have been far from ideal - the visitors will be without Daniel Sturridge, Danny Ings, Jordan Henderson and Joe Gomez, while Christian Benteke is a doubt. The Blues, meawhile, will be hoping Diego Costa and Pedro are fit enough to feature.
Regardless of both starting line-ups, though, the storyline will ultimately focus on the opposites in the dugout. Mourinho's war mode is countered by Klopp's megawatt smile. It is fatalism versus optimism.
Mourinho has never marked a fourth anniversary with any club - his 15 years of management have been split between six sides, the second spell at Chelsea being his seventh different stint. Klopp's 14-year career, meanwhile, was equally shared between Mainz and Dortmund. He will want to be at Liverpool for the long haul, too.
Former Madrid boss Mourinho seems equally disliked as he is respected. His caricature as a bully is in contrast with Klopp's geek-like charm. The philosophy of the Chelsea boss is to win - whatever form that takes. And he has been quite special at it, as his two Champions League wins and title victories in four different countries prove.
The German prefers an unmistakable style - you are guaranteed that a Klopp team will counter-press, be compact, aggressive, dynamic and work harder than their opponents.
When Dortmund were at their lowest, the club were desperate to hold onto Klopp. Mourinho, it seems, doesn't have that sort of backing.
For all their differences, the duo share more similarities than just a recent, excruciating fall from the top. The success story of Mourinho's Porto reads like BVB's fairytale with Klopp. Both men forged very strong, very distinct managerial careers on their own terms. Both have the ability to hypnotise players and get their full cooperation. Mourinho and Klopp are a media dream, albeit in different ways.
And so the interest will be immense as these top-tier managers - or 'friends' as they both would have it - tussle again. Mourinho has only won one of his previous four meetings with Klopp, but is in desperate need of another. He has suffered defeat in six of his last 12 Premier League matches but, immediately before that run, it took him 64 games to reach the same number of losses.
It feels like the 52-year-old is hurtling towards the end of his reign at Chelsea as Klopp is enjoying the start of his at Liverpool. After being linked with the reigning Premier League champions months ago, a victory for Klopp on Saturday could be the final nail in Mourinho's coffin.
