"I believe when Rio or Lamps or Joe Cole were coming through they were just promising. Then they improved," the Italian said.
"What I said about my players is that it is just down to them. If they work hard every day and keep the right attitude they can do that.
"Maybe Harry has more experience than me and can see forward more than me. But I believe everyone owns their own destiny.
"When I started playing football there were a few that said I wouldn't become the player I was but they didn't know what my attitude and mentality was.
"I believe that if my players have the attitude they can become important players.
"If they push themselves hard and believe in what they do they will go beyond the limits that people are putting on them now."