Chelsea boss Antonio Conte insists he can still improve David Luiz, despite him being almost 30 years of age.
To highlight how much hard work can pay off, Conte cited the Italy and Juventus combination of Andrea Barzagli, Leonardo Bonucci and Giorgio Chiellini whom he knows so well.
Conte said, "It is important to remember that when I started at Juventus with Bonucci and Chiellini and Barzagli, the defence of Juventus conceded a lot of goals. I remember before I arrived many people told me they are not good these defenders or they are good these defenders.
"I started to work with them and found a great commitment from these players and then through the work I think now we are talking about three great defenders in the world. But I remember when we started, it wasn't so.
"I think David Luiz's qualities are somewhere in the middle between Bonucci and Barzagli. He is good technically and has good personality like Bonucci, and he likes to play football like Bonucci likes to play football, and also I find the good physical potential like Barzagli."