De Ligt insists he's grown over the past two seasons.
He told De Volkskrant, “I've grown so much mentally and feel far more mature since I've been at Juventus.
“I had to get used to a different style of football in Italy, the way the forwards move. When I was at Ajax, the focus was far more on the individual striker, whereas now I have to look at the zone too. Don't always chase the man with the ball, but also keep an eye on the striker who is running into space. It's all about evaluating the best option.
“Chiellini is a master in that sense. He has so much experience, I learned a great deal from him. Defending is an art form in Italy, it's wonderful to be able to show what I can really do here. That was my objective."
De Ligt also said: “The way Cristiano Ronaldo lives the sport, keeps himself in shape and is so motivated at the age of 36 is fantastic. The same goes for Chiellini and even Gigi Buffon at 43. They are all super professional."