Rafa Benitez was the Napoli coach who signed Kalidou Koulibaly in 2014, so he predicts where the Senegal international will shine at Chelsea and what he needs to be wary of.
The defender made the €40m transfer – including add-ons – to Stamford Bridge and signed a four-year contract with option for a fifth.
It is a big step for the 31-year-old, who had been at the Stadio Diego Armando Maradona since Benitez urged Napoli to purchase him for €7.75m from Belgian side KRC Genk in 2014.
Koulibaly has become a hero in Serie A, but Benitez is a coach who has plenty of experience in both the Premier League and Italian football, so nobody is better placed to predict how this move will go.
“He has played as a right and left central defender in a line of four or even with three,” Benitez told The Athletic.
“With us, also he played as a right-back in a line of four. He is versatile for a defender — he is quick and good in the tackle.”
Romelu Lukaku is someone who found his extraordinary physicality make the difference in Italy, but not so much in England.
“This season will be the Premier League for him and he could be fine for the way that Thomas Tuchel wants to play. He has similarities with Antonio Rudiger — he is very good at running with the ball, he’s good with both feet.
“Is he a little bit too nice? We will see what happens at Chelsea. As I said, in Italy he was fine because he was so quick, but I doubt he will be so dominant over here.
“Aerial ability wasn’t his biggest strength but in Italy that mattered a bit less and he was ok. It will be interesting to see how that develops in the Premier League but he was always very keen to learn and he spent time with me and my staff after training sessions to work on his heading and improving his technique.”
Benitez warns there is one area where Koulibaly could struggle and that is the pace of the game, rather than the pace of the players.
“He must improve his concentration at times. He can be guilty of losing focus and can be overconfident, but he has been hugely influential at Napoli and people I know and trust have told me that he has been the best centre-back in Italy during this time.”
Benitez has the cheek to talk about improvements. He was like this at Real Madrid and went so far as to tell Ronaldo how to improve. Look at his managerial career now.