When Jurgen Klopp arrived in Liverpool in October 2015 to take over the Anfield club, he did so as one of the most well-respected managers in all of Europe.
His reputation was built on a seven-year stint in charge of Borussia Dortmund during which time he took the Bundesliga club back to the top of German football and wrestled away two league titles from the powerhouse that is Bayern Munich.
His managerial resume also includes a last-minute Champions League Final defeat, numerous then-league records with Dortmund and, since joining Liverpool, a Europa League runners-up medal. However, revealing this week what his greatest achievement in football was, the German boss mentioned none of the above.
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Instead, according to Klopp himself, his best footballing feat came when, in 2004, he took his home town club, Mainz 05, to the Bundesliga for the first time in their history.
"That promotion is still the biggest achievement in my professional life,” Klopp told the Liverpool Echo ahead of Liverpool's friendly against his former club on Sunday.
“To do that with Mainz was much more difficult than becoming champions with Dortmund.
“When you miss out two times in a row like we did, missing out by one point and one goal, then to think of more pressure is not possible.
“What we did then was unbelievable. It was the first time in 100 years. It was a wonderful team and squad. I had a fantastic time."
Klopp clearly has a great affinity with Mainz, and getting the provincial club into the German top flight was certainly some achievement. The fact that he took them to what was then a UEFA Cup spot in their debut season is perhaps even more impressive.
Of course, Liverpool fans will be hoping that the 49-year-old will have reason to replace his rather unexpected pick in the not too distant future.
With Liverpool having struggled for consistency in recent years, there's no doubt that if he were able to bring the Merseyside club their first title in over 20 years it would surely have to go straight in at the top of his list of footballing achievements.
Just how long Liverpool fans will have to wait before that eventuality becomes a reality, however, remains to be seen.
The Anfield club impressed at times during Klopp's time in charge last season and have strengthened in a number of areas this summer.
Unfortunately for them, so have virtually every other team set to fight it out in the higher echelons of the Premier League this year.