Perez has informed Mourinho he plans to try again to sign United goalkeeper David de Gea in 2018.
Diario Gol says Mourinho accepts he can't shake Perez's pursuit, but will insist he pay top price for the Spain No1.
Along with a big cash component, Mourinho also wants a star player in the deal and has demanded Perez include Marcos Asensio in their offer.
For his part, Perez has told Mourinho directly that Asensio is not for sale, despite the player expressing frustration over his playing opportunities. The United manager has been told the midfielder would be open to a move, but Perez has made it clear he will not be allowed to leave.
Instead, Perez is pushing Mourinho to accept Gareth Bale as part of a swap. The United manager hasn't ruled that out, but the valuation of the Welshman will be critical given his injury record.