Speaking about the saga, Benitez said: "Javier has a very good friend in the national team and that is Messi.
"Messi was on to him every day and that is not easy, but Javier knows what we think of him and he will be okay."
Now that Mascherano has opted to stay, Benitez is expected to work out a new contract for the player, who had appeared to fall out of love with life in England in the light of Barca’s interest.
Benitez added: "I talked with Javier, his agent and Barca. It is normal they see him as such a good player, and an option for them.
"We told Javier he was so important for us and we wanted to keep him. We were not talking about any price.
"He was a bit disappointed as it was a fantastic opportunity with a big club. But he is happy here, and as a player and a person you can trust him 100%."