Vieira says the Italy striker is in confident mood going into the quarterfinal against England.
He said: "I have heard from Balotelli two or three times recently, as we exchanged some text messages. I complimented him for the goal against Ireland and he seemed happy.
"Mario worked for the team against Spain, better than he usually does in Manchester, and above all did his duty off the ball. It's what Roberto Mancini asks of him, though I don't know if he has more faith or more patience with Mario..."