Reds supporters have been hyped on Twitter for the arrival of the 23-year-old, who was presented with his new number 8 shirt by club legend and current Rangers manager Steven Gerrard.
Keita joins the club after Liverpool and RB Leipzig came to an agreement last summer. The Reds will pay around £52.75 million after Leipzig missed out on Champions League qualification, as reported by the Liverpool Echo.
The dynamo spent the day undertaking media duties with the club and had his first training session at Melwood, and Liverpool supporters were delighted.
News also filtered through on Wednesday that Manchester United midfielder Marouane Fellaini is set to extend his contract at Old Trafford by two years.
As reported by ESPN, there was every expectation that the Belgian midfielder, currently on World Cup duty, would move on when his current deal expired on June 31, but the former Everton man appears to have done a complete U-turn, and it has not gone down particularly well with United supporters.
For a lot of them, it is not so much the offering of a new deal to Fellaini, who has his own useful qualities, but the comparisons against Liverpool and the fact they have announced Keita - a supremely talented, young and dynamic central midfielder.
Here are some of the best responses:
Liverpool unveil Keita and Fabinho— The United Stand (@UnitedStandMUFC) 27 June 2018
Arsenal chasing Banega and Torreira
City adding Jorginho to a top class midfield
We beg Fellaini to stay
That is all
So LFC is announcing Keita on 1st July and we’re announcing Fellaini’s new contract on the same day.Okay!!!! Im done with twitter today.— EmmaRoseBrown (@EmmaRoseBrown4) 27 June 2018
Liverpool announce Naby Keita while United extend Fellaini contract pic.twitter.com/ZfZvH3RhmX— C (@naitsye) 27 June 2018
On the day Liverpool announce Naby Keita, rumours about Fellaini signing a new 2 year contract at United surface.. pic.twitter.com/AVenwjDsao— Dark Vader (@omwami_4) 27 June 2018
Liverpool just signed Keita and we’re begging fellaini to stay♂️— baghdaddy (@ClinicalFred19) 27 June 2018
What hurts most about Fellaini renewing is that Liverpool just announced Naby Keita.— Lush (@Luciah_PS) 27 June 2018