Super agent Jorge Mendes is demanding Barcelona pay Ansu Fati what he's worth.

Mendes has taken over the affairs of Fati from Rodrigo Messi, Leo's brother, and is negotiating the teen's new contract.

Mundo Deportivo says once Fati is formally confirmed as a first team squad member for the new season, his contract will see it's buyout clause jump from €170m to €400m. An improvement in wages is also expected.

Barca have confirmed they turned down an offer of €150m - believed to be from Manchester United - for Fati and Mendes is using that news as leverage.

The Portuguese is insisting Fati's salary come in line for a player worth more than the €150m president Josep Maria Bartomeu refused to accept earlier this summer.