The 24-year-old scored an 11-minute hat-trick, his first in the Champions League, won a penalty and provided an assist for his side’s impressive 5-1 win against the Serie A outfit.
Sterling has also scored six times in the Premier League this season including a hat-trick against West Ham United in early August.
Such impressive form has forced Ferdinand to rank Sterling among the best footballers in the world.
"We are running out of great words to say about him," Ferdinand said on BT Sport.
"He is a young English player who has played a lot of games. He is still improving and adding more to his game. He has a striker's nose to get into certain areas.
"He is in the top five players in the world now. Definitely! I don't care who you mention. The effect he is having, the goals he is scoring, it is impossible to keep him out."
Ferdinand took time to praise Manchester City manager Pep Guardiola for his immense contribution on Sterling since his arrival in the Premier League.
"Sometimes you are blessed to get a manager to learn from," he said. "Pep Guardiola coming at the time he did, to coach this young player with immense potential."
Sterling has become one of the linchpins of Guardiola’s Manchester City and has already scored 12 goals and provided four assists in 13 matches so far this season.
