Napoli defender Kalidou Koulibaly credits coach Maurizio Sarri for his progress.

Koulibaly is now regarded among the best defenders in the game.

He said, “My first season was needed to adjust, as I had to learn and understand Italian football, but with Sarri's arrival, I made enormous progress.

“We learn something new from him every day and in tactical terms, Sarri really perfected us. We just keep improving."