The Red Devils are very keen to bring the Juventus forward to Old Trafford this summer.
However, the deal might be on the brink of collapse, with Antun’s demands.
United chiefs have been meeting with Juventus officials in London since Thursday, in a race to complete the deal before next week’s deadline.
The majority of terms are thought to be agreed, including Romelu Lukaku’s switch to the Serie A club in exchange.
However, the Dybala end is still uncertain, with the player also concerned about the lack of Champions League football.