Liverpool head coach Jürgen Klopp has said that Robert Lewandowski is the best player he has worked with in his time as a coach following the pair's time together at Borussia Dortmund.
Klopp was the head coach at BVB between 2008 and 2015, bringing Lewandowski to the Bundesliga from Poland in 2010 before the joint-second all-time top scorer in the German top-flight went on to join Bayern Munich in 2014.
Despite managing the likes of Mohamed Salah, Virgil Van Dijk and Sadio Mane in his time at Liverpool in the English Premier League, Klopp has said it could only be the former Dortmund No.9 when asked about the best player he worked with.
Watch: Klopp - Made in the Bundesliga
"Robert Lewandowski," Klopp said when asked the question by Lothar Matthäus for SportBild. "It would actually be unfair to say that about any other player than Lewy.
"What he made out of his potential, how he pushed himself to become the player he is today, that's extraordinary."
Lewandowski scored 103 goals in 187 appearances for the Black-Yellows, all under the stewardship of Klopp. The pair won three titles together in their time at the Signal Iduna Park, clinching two Bundesliga titles and a DFB Cup before Lewandowski's departure to the Allianz Arena.
The love shared between the two is mutual, as Lewandowski revealed the "father figure" that Klopp became for him at Dortmund in an interview with The Players' Tribune.
"Jürgen was not only a father figure to me, as a coach, he was like the 'bad' teacher. And I mean that in the best sense of the word. He was not content to let you be a B student, you know? Jürgen wanted A+ students. He didn't want it for him. He wanted it for you. He taught me so much. When I arrived at Dortmund, I wanted to do everything quickly: strong pass, one touch only. Jürgen showed me to calm down - to take two touches if necessary.
"It was totally against my nature, but soon I was scoring more goals. When I had that down, he challenged me to speed it up again. One touch. BANG. Goal. He slowed me down to speed me up. It sounds simple, but it was genius, really."