Former team-mate Timo Werner claims the midfielder has the chance to show what he’s capable of now he’s joined the Reds.
In a protracted transfer saga, Keita actually agreed to join Liverpool last August.
The Anfield outfit triggered the Guinea international’s £48m release clause in addition to paying a premium dependent on their league finish.
Keita will finally become a Liverpool player on July 1, after a difficult final season in Germany with saw him sent off three times.
Werner, himself linked with a high-profile move to the Premier League, is convinced that the 23-year-old will grab his opportunity with both hands.
Speaking to Die Welt, Werner is quoted as saying: “To become world-class you have to play in the big teams and then play big games like the final or semi-final of the Champions League.
“World class… I’m not yet a world class striker. For me (Robert) Lewandowski, Luis Suarez and Antoine Griezmann are.”
“To become a world class player, I probably have to play on a club level in an even better team.
“Naby Keita has not become world class with us either, maybe now he’ll be at Liverpool.
“I have four or five years left to learn, and then become world class.”
Liverpool reached the Champions League final for the first time in a decade this season.
Despite matching Real Madrid in the early stages, Jurgen Klopp’s men were undone by an injury to Mohamed Salah and catastrophic goalkeeping by Loris Karius.