Silva, a member of City's FA Cup-winning side last season, also caught the eye with a double strike in Spain's Euro 2012 qualifying win over Scotland last week.
Mancini, the former Inter Milan boss, said: "I think Silva is one of the best players in Europe and the world.
"He has improved a lot in the last year as a guy and as a player.
"I saw him for the first time when I played in the Champions League several years ago - Inter v Valencia. He was young then but he was incredible."