Klopp and Wagner: From Mainz men to main men in the Premier League
Jurgen Klopp and "best friend" David Wagner will occupy opposing dugouts at Anfield on Saturday, but only one would be on the bench when they first met at Mainz 26 years ago.
The current Liverpool and Huddersfield managers became acquainted on the banks of the Rhine in 1991 after Wagner, four years Klopp's junior, arrived from Eintracht Frankfurt.
"When we first met up at Mainz he was a striker and I was a striker," Wagner explained to the Daily Mail shortly after taking the Terriers post in 2015.
"He was the main one when I signed from Eintracht Frankfurt in 1991. Then I took his place and he sat on the bench - this was the start of our relationship."
It was an inauspicious start. Yet Klopp would revert to defence and the player who took his spot in the team soon became a close friend, one who would take on best-man duties when the Liverpool manager got married.
Wagner does not recall how his speech in a Mainz restaurant went having overdone the Dutch courage, though their friendship would endure, even after he left for Schalke in 1995.
Klopp's association with Mainz would span almost two decades and take him from the pitch into the dugout when he graduated to become manager in 2001. He left for Borussia Dortmund seven years later and Mainz laid on a farewell party, which Wagner attended wearing a back-to-front shirt featuring his mate's name.
The prospect of the two crossing paths in a professional capacity again seemed slim when Wagner, upon retirement, went to university and then became a full-time teacher after gaining a degree in biology and sports science.
Yet they were reunited at Dortmund in 2011, Wagner taking charge of Borussia Dortmund II where he nurtured the likes of future Germany international Erik Durm for Klopp's senior side.
In 2015 it was Klopp who would leave his buddy behind as he bade farewell to Dortmund and later that year he joined Liverpool.
England would be Wagner's next destination too but, less one month after Klopp took on the Liverpool job, the pair would not be working at the same club again as many thought.
This time the apprentice wished to be the master, at Huddersfield, with Klopp recommending he "just do it" when Wagner asked if he should accept the offer.
On Saturday the two managers will meet on a level playing field after Wagner led the Terriers back to the top flight following a 45-year absence.
There are plenty of parallels between the pair, not just with their football philosophies but also in their appearances - the baseballs caps, beards, spectacles and tracksuits - as well as the press conference quips and the displays of touchline emotion.
Wagner has spent the past two years being known as 'Klopp's mate' in England but victory over the Reds on Saturday would see his team go above Liverpool in the Premier League table.
Fortunately, they have proven their friendship would still survive.