Chelsea boss Thomas Tuchel has dubbed Kalidou Koulibaly a "brilliant signing".

The former Napoli joined the Blues squad in Las Vegas on the weekend.

Tuchel said, "He brings experience, top defending quality, height, and everything we are looking for to play in a back-three or a back-four.

"It's another brilliant signing for us, and we hope Kalidou can show his quality as soon as possible.

"He knows already some of the players. He plays with Edouard Mendy with his national team and he played with Jorginho at Napoli. I think for this side it will be very quick that he feels welcome in the group. It's a nice group, and everybody is happy that he is with us now."

Koulibaly has penned a four-year contract and Tuchel added, "He is totally fit and ready for the challenge, and he needs to be because we need him in top shape."