Mascherano joined Barca from Liverpool in a £22million deal earlier this week.
Messi said: “He’s a great player. In addition to what he can do in football, his arrival is a joy for me.
“Barcelona wanted him for what he means as a player and as a person, I am very glad that he signed.
“He’s a great player, he really helps us, hopefully this season we can keep winning titles with Barcelona’s shirt.”
