Mascherano has been linked with a move to the Giuseppe Meazza since former Liverpool boss Rafa Benitez took charge of the Italian side.
“We are very excited about Mascherano joining us at Inter,” Milito said in the Daily Star Sunday.
“He has made it clear he wants to be here and it’s just down to the relevant people agreeing the deal now.
“In my view we are getting the very best defensive midfield player in the world and Maradona calls him one of the three most important players in the Argentina squad along with Lionel Messi and (Carlos) Tevez. That’s how highly he is regarded.”
Milito added: “I think it’s unrealistic of Liverpool to think they can keep hold of Mascherano when they can’t even offer Champions League football and are not challenging Manchester United and Chelsea for the Premier League title.
“The boss and Mascherano have a good friendship so there were no other clubs on the cards for him after that, including Barcelona. He has wanted to join for a while but when the boss joined Inter I think that sealed the deal.
“Rafa has already made it clear that he wants another season like Jose had with us last season. Javier is a natural-born winner.
“He’ll relish being at a club where he will win top honours.
“I think it will be hard for Liverpool to hold on to the top players, including (Steven) Gerrard and (Fernando) Torres, but that is not my concern.
“I would like Tevez to join us as well but I don’t think that will be possible this summer.
“Manchester City are in a position where they don’t have to sell, but Carlos has told me he would like to play in Italy in the future.”