Roberto Firmino has been torn apart by his former club chief Ernst Tanna at Hoffenheim
The Brazilian forward has been an integral part of Liverpool's success in recent years.
Since joining the Reds in 2015, Firmino has been able to establish himself as one the Reds' most prominent players under boss Jurgen Klopp.
Hoffenheim snapped up Firmino's signature in 2011 from Brazilian outfit Figueirense.
According to Tanner who was sporting director for the Bundesliga club then, there were some displeasing stats about Firmino's level of fitness when he newly arrived Europe.
"You should have seen the data that we got on him when he was coming for the first time [to Hoffenheim],” Tanner told Bleacher Report.
"In Germany, we usually do these endurance tests, blood ones, which are pretty accurate, you know, and he had the worst numbers I have ever seen in professional football.
"I would say to emphasise that he was even worse than my grandma. You can't imagine.
"They were so low that you couldn't even believe that he was ever able to play professional football.
"While lambasting earlier on Firmino's fitness, Tanner also revealed he never had any doubts over Roberto Firmino’s ability and potentials to thrive in European football.
"I was pretty sure that he would be a top Bundesliga player. We do these evaluations in our scouting reports, you know, and I think that out of 10, nine and 10 are international level. And I gave him, I don't know if it was an eight or nine, but I'm sure it was pretty high," Tanner added.
"Everyone [at Hoffenheim] was a bit curious about that at the time, but I rated him pretty high because I was so convinced about his abilities and even more so by his attitude.
"When I saw how the coach criticised him [in a training with Figueirense], he was like a schoolboy standing there and listening to his teacher. I still have that picture in my brain.
"I thought to myself after an hour that if that coach had done that to a German player, he would head straight to the locker room totally pissed off, but Firmino took the criticism well. He tried to improve, to do better. That was really impressive."