Thomas Tuchel hopeful Kalidou Koulibaly can emulate Thiago Silva

Chelsea head coach Thomas Tuchel believes new signing Kalidou Koulibaly can emulate fellow centre-back Thiago Silva and play well into his 30s.

Koulibaly has completed a €40m (£34m) move to Chelsea from Napoli, signing a four-year contract at Stamford Bridge before flying out to Las Vegas to join the Blues' tour of the US.

Following Chelsea's 2-1 victory in their first pre-season friendly of the trip against Club America - a game in which Koulibaly did not feature - Tuchel expressed his delight at the signing.

"He brings experience, quality, top defending, quality, height, everything we're looking for to play a back three of back four," he said. "It's a brilliant signing, another brilliant signing for us, and we hope that he can show his quality as soon as possible.

"He is now training outside after he arrived yesterday, and we've very happy. He knows some of the players - he plays with Edou [Edouard Mendy] with the national team and knows Jorgi [Jorginho] from Napoli - so I think from this side, it will be quick that he feels welcome in the group. It's a nice group, and everyone is happy he is with us now."

Despite being 31 years old, Koulibaly has been handed a four-year contract in west London. Tuchel was asked whether that meant there was a belief that Koulibaly could follow in Silva's footsteps and play well into his late 30s.

"That's what we believe, and that's what he is here for," the German responded. "There were always rumours about him leaving Napoli, and it was always super difficult – and in the end impossible – to get him because he was a key player.

"It's nice he takes the challenge right now, and we have Thiago Silva, who is even older and super experienced and still at the peak of his game. We hope Kalidou can do the same and play for many years for us. He is totally fit and ready for the challenge, and he needs to be because we need him in top shape."