The France international "can be one of the best", according to the Argentine, who also expressed admiration for Frenkie de Jong and Matthijs de Ligt.
Lionel Messi believes that his talented Barcelona team-mate Ousmane Dembele is a "phenomenon" who is capable of ranking among the best players in the world.
Dembele, 21, has scored seven goals in his second season in La Liga so far and netted three times in four appearances prior to the mid-season break.
That excellent run of form stifledÂ speculation over the France forward's future, with his place at Camp Nou having been called into question following a range of disciplinary issues.
Barca captain Messi lauded the World Cup winner's potential and insistedÂ the club areÂ committed to nurturing his development.
"On the pitch [Dembele]Â is a phenomenon and it depends on him [how good he becomes]," the 31-year-old told Marca.
"He has all the opportunity in the world to do what he wants. He can be one of the best.
"On the other hand, he's a young guy who is adapting to the city and the club. The less you speak about it, the better. It's necessary to leave him so he can be calm.
"He has already realised his mistakes and has rectified them. We are going to help him focus on football."
Dembele appears increasingly likely to stay at Barca long-term and could be joined by promising Ajax youngsters Frenkie de Jong and Matthijs de Ligt if the La Liga champions are able to land their prime targets in the transfer window
Midfielder De Jong is tipped to link up with Messi's side at the end of the season while teenager De Ligt has been a mentioned as a possible defensive reinforcement.
The Argentine is certain the pair would fit comfortably into Ernesto Valverde's squad.
"They come from a school very similar to ours and they work in the same way. They play like us, with the ball," he added.
"They are young players with great precision.Â Two very good players."
Barca do not return to action now until January 6 when they travel to Getafe in La Liga.
They then head to Levante four days later on January 10 for the first leg of their Copa del Rey last 16 clash.