The Poland striker became a star under the manager's stewardship and is now one of the deadliest scorers in the game
Liverpool boss Jurgen Klopp has singled out his former Borussia Dortmund charge Robert Lewandowski as the finest talent he has taken under his wing as a coach.
Klopp has built memorable teams at both Liverpool and BVB, winning the Premier League and Champions League with the former,, and having taken the Germans to back-to-back Bundesliga success in 2010-11 and 2011-12 - the last time a team other than Bayern Munich finished top of the pile.
Over that time he has taken charge of countless world-class players, but one in particular stands out for the 53-year-old.
What was said?
When asked during an interview with Bild who was the best player he had worked with as a manager, Klopp did not hesitate in his answer.
"Robert Lewandowski. It actually won't be fair to say that about any other player except Lewy," he explained.
"What he has made out of his potential, how he pushed himself to become the player he is today, that's extraordinary."
According to the coach, it is not just the Poland international's innate ability in front of goal that makes him such a fine player, but also his work ethic and determination.
"Lewy took every step he needed to take to be that goal machine. Every one," he added.
"He has immersed himself in the game, he just knows in every situation what he has to do, where he has to go. Lewy is an absolute machine."
The bigger picture
Lewandowski and Klopp first linked up in 2010, when the Dortmund coach swooped to sign Lech Poznan's promising striker, who was just 21 at the time.
The pair spent four seasons together at Signal Iduna Park, during which time BVB lifted their two aforementioned Bundesliga crowns and the 2011-12 DFB Pokal to complete a domestic double that term, also reaching the Champions League final the following year where they lost out to Bayern.
Lewandowski scored 103 goals in 178 appearances for the Rhinelanders before he left for their Klassiker rivals in 2014 on a free transfer.
Klopp was on the move the very next summer, resigning after a disappointing season where Dortmund finished seventh in the Bundesliga standings.