Sao Paulo are ready to block any attempt made by Manchester United to land £26m-rated Lucas Moura.
The midfielder, 19, is believed to figure on Sir Alex Ferguson's summer wishlist.
But his hopes of landing Moura have taken a hit, with his Brazilian club saying they are ready to take a gamble by hanging on to him.
Sao Paulo president Juvenal Juvencio said: "It is a risk not selling Lucas but we are going to take it."
It could be a ploy to try to drive the price up further but United are not willing to be held to ransom.