The Paris Saint-Germain boss believes there is no limit to the young forward's potential
Paris Saint-Germain coach Thomas Tuchel praised the "incredible" Ousmane Dembele, but added the Barcelona star was "a little crazy".
Dembele has faced criticism over his discipline this season, but has also found form for the La Liga giants.
The 21-year-old has often infuriated Barca coach Ernesto Valverde by turning up late for training, but is also capable of moments of inspiration on the field.
The forward has scored 10 goals and provided five assists in 23 games in all competitions, helping Barca sit five points clear at the top of the league table.
Tuchel worked with Dembele for a season at Borussia Dortmund during the 2016-17 campaign, with the young forward thriving under his tutorship.
He scored 10 goals and added a further 21 assists for the Bundesliga side, prompting Barcelona to spend €105million (£94.5m/$120.3m) plus add-ons for his services in the summer of 2017.
Though it hasn’t always gone to plan for Dembele at the Camp Nou, Tuchel insists there is no doubting the France international's talent.
"Ousmane is an incredible player, he's really talented. I could watch his amazing skills in every training session," he told a news conference on Tuesday.
"He's also a great human being. He's a little crazy. He's a really nice boy but a little crazy. He loves to laugh but can also have very serious conversations. It's never boring with him.
"If he's focused enough, he can reach any level. When I talked to him for the very first time, he told me that he wanted to play for Barcelona. That's where he is now.
"It means he can reach any level, but he needs to remain focused and improve each day. During training sessions he was as talented using his left or right foot.
"He's a good boy. I had a good year with him."
Tuchel's PSG face Guingamp in the Coupe de la Ligue quarter-finals on Wednesday.
Next up for Dembele’s Barcelona is a trip to Levante in the last 16 of the Copa del Rey on Thursday. The Blaugranes then return to league action against Eibarat the Camp Nou on Sunday.