With the Reds now back on Merseyside and preparing for a final pre-season friendly against Blackpool, Koumetio has remained with the first team after a surprise call-up.
The 17-year-old looks to have jumped ahead of Nat Phillips, Sepp van den Berg and Ki-Jana Hoever in the pecking order having been named on the bench for the Community Shield, and is likely to feature on Saturday.
It is an impressive rise for a player who, though built like a senior centre-back, is hugely inexperienced, having only made 12 appearances in his debut season with the Liverpool academy in 2019/20.
Klopp took time to work one-on-one with Koumetio in a training session on Thursday, with the manager taking a vested interest in his No. 89, who is a candidate for fourth choice behind Virgil van Dijk, Joel Matip and Joe Gomez.
Koumetio is likely to spend much of the new campaign with the under-23s, however, and speaking to The Redmen TV, their coach Barry Lewtas assessed his progress so far.
“First and foremost, he’s a young kid, he’s 17 still,” he stressed.
“I think it’s a fantastic opportunity for him to get away and travel with the first team.
“He’s not the first to have done that, we’ve been extremely fortunate over the last few seasons that the manager has been extremely welcoming of young players from the academy.
“Not just on pre-season tours but during the season, being around Melwood and being around first-team players.
“Obviously Billy’s the next one in that line. It’s great when you see a young boy go up and have that experience, so I’m over the moon for him.
“He’s definitely not the first, and the way things have been he’s not going to be the last either.
“I’m sure at some point he’ll be back with us training, working hard and he will have had a taste of it. I’m sure he’s had a fantastic opportunity and an unbelievable experience.
“Playing with the players he will have played with and obviously under the guidance of the staff at Melwood will have been an unbelievable experience for him.
“So once he’s back I’m sure he’ll knuckle down and he’ll want a little bit more of a taste at another point.
“In a few months time it might be someone else, and then someone else; that’s the beauty of the academy really, that’s what we want.”
As Lewtas attests, there is a long line of talent in Liverpool’s academy that could step up into Klopp’s plans in the coming months, with Leighton Clarkson, Jake Cain and Paul Glatzel all having been involved at senior level this year.
But for Koumetio, there is currently a clear pathway for a place in the squad, and his continued presence at Melwood suggests he could move forward quicker than many of his young team-mates.
“It’s a big question,” Lewtas added, when asked if the Frenchman has what it takes.
“He’s certainly a player with potential, he’s got a fantastic personality, he’s a real good boy to work with.
“He wants to learn, he wants to get better and it’s up to him to make sure he fulfils his potential.
“Along with that, it’s up to us to give him the support and the guidance, and help him reach his potential.
“But he is only 17, he’s only a young boy. He’s got fantastic attributes, but let’s see.”
Lewtas is right to downplay the situation for Koumetio, but it is encouraging he highlighted his “fantastic personality” along with the clear physical and technical qualities he possesses.
Character is as important as ability for Klopp, and the manager will be learning more about his latest addition as they continue to work together at Melwood.
From the outside looking in, it seems as though Koumetio is developing into a project for Klopp, and perhaps this is a sign that he is being nurtured as the immediate successor to Dejan Lovren.