Sao Paulo director Marco Aurelio Cunha has told Manchester United that they must increase their offer if they are to sign Lucas Moura.
Moura, 19, has been strongly linked with both United and Inter Milan this summer, but the Brazilian outfit have insisted that they will not sell below their asking price.
"Manchester United made a very important offer of £27m, but they would need to produce a little more," Cunha told TMW.
"For us, only Neymar [in Brazil] is worth more. After him is Lucas, and we would not want to sell for less than this sort of value."
It is understood that Sao Paulo value Lucas at £40m.