Former Chelsea manager Rafael Benitez has admitted Kalidou Koulibaly must improve his concentration levels ahead of playing for the Blues.

The defender recently completed a £34million switch to Chelsea from Napoli and is expected to fill the void left by Antonio Rudiger, who has joined Real Madrid on a free transfer.

But the former Chelsea boss Benitez, who tutored Koulibaly during his time at Napoli, has shared his concerns over the defender losing focus on the pitch and his tendency to be quite ‘overconfident’.

Although, Benitez admits that the 31-year-old was highly influential for Napoli but will need to raise his levels because it is different in the Premier League.

He told The Athletic: ‘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.

‘This season will be the Premier League for him and he could be fine for the way that Tuchel wants to play.

‘He has similarities with Rudiger – he is very good at running with the ball, he’s good with both feet.’

‘As I said, in Italy, he was fine because he was so quick, but I doubt he will be so dominant over here.’

Benitez has also pointed out that while Koulibaly’s aerial ability was not the best, he was always willing to try and improve and take on advice from the coaches.

‘Aerial ability wasn’t his biggest strength but in Italy, that mattered a bit less and he was ok,’ he said.

‘It will be interesting to see how that develops in the Premier League but he was always very keen to learn.

‘He spent time with me and my staff after training sessions to work on his heading and improving his technique.’

Chelsea begin US tour on a winning note

Thomas Tuchel’s side were in action on Saturday night as they faced Club America.

Timo Werner handed the Blues the lead, before Reece James’ own goal leveled matters for the Mexicans. Mason Mount then popped up with the winner in the dying embers of the game.

Hakim Ziyech, who has been linked with a move to AC Milan, also took part in the game including Conor Gallagher and a host of others.

Chelsea will now face Charlotte FC on Thursday in the next step of their tour across the United States