Chelsea were willing to make Napoli defender Kalidou Koulibaly the most expensive defender in the world according to the Naples club's chief Aurelio de Laurentiis. The Blues were linked for most of the summer with the Senegalese defender, but were unable to convince the Serie A club to sell.

Antonio Conte had made strengthening his defence a priority, but failed to land any of his preferred targets. This prompted the club to make deadline day moves for former Blues star David Luiz and former Bolton defender Marcos Alonso from Paris Saint-Germain and Fiorentina respectively.

Chelsea pursued the defender until the final days of the summer transfer window and had a number of bids rejected after the defender's agent had earlier admitted that a summer move was possible after they reached a stalemate with Napoli. The Italian club, however, were adamant that the defender is not for sale and finally reached an agreement with the player on a five-year deal that was signed last month.

De Laurentiis has confirmed that a final bid of €58m (£51.1m, $64.9m) was submitted in the final days of the window, which was rejected by the club. The Serie A club's chief, however, has admitted that they could consider selling the Senegal international next summer, but are likely to demand a hefty fee after tying him down to a new deal until 2021.

"In the last few days of the transfer market, I refused an offer worth €58million for Koulibaly. Conte will say that it is not true, but he offered 30, then 40 and then €50million," De Laurentiis said, speaking at the Leaders in Sport Business conference, as quoted by Goal.com

Kalidou Koulibaly
Kalidou Koulibaly was Antonio Conte's priority summer target to strengthen Chelsea's defence Getty

"But I had already made the decision for myself that he would stay put for another year. We can talk again next year..." he added.