Chelsea faced competition for the signature of Napoli defender Kalidou Koulibaly. Catalan giants Barcelona were reportedly also interested in signing Koulibaly. The 31-year-old Senegal international looks set to join Chelsea this summer after the Blues reached an agreement with Napoli for his signature.According to Sport, Barcelona requested Koulibaly to put his potential move to Chelsea on hold and wait for them instead. The defender, however, is close to joining Thomas Tuchel's side in a deal worth €40 million. He is expected to sign a long-term contract with a €10 million-per-season salary package as per transfer expert Fabrizio Romano.Footy Accumulators@FootyAccumsBarcelona want Kalidou Koulibaly to wait for them, but Chelsea are pushing to sign him.[Di Marzio]Of course they do 🙄1908Barcelona want Kalidou Koulibaly to wait for them, but Chelsea are pushing to sign him.[Di Marzio]Of course they do 🙄 https://t.co/Oy9Tz3wfhhBarcelona are believed to be interested in signing Koulibaly as they view him as a potential replacement for veteran defender Gerard Pique. The 35-year-old has been unable to maintain the consistency and level of performance that has made him a legend at Camp Nou.Barca will therefore be eager to sign a world-class defender capable of providing leadership as an adequate replacement for Pique.Kalidou Koulibaly joined Napoli from Belgian club Genk in 2014. He has made 317 appearances in all competitions for the Italian giants and has become one of the best defenders in Serie A.The 31-year-old has just one year left on his contract with Napoli and reportedly rejected the chance to extend his deal with the club as per Daily Mail. The club have therefore seemingly opted to sell the defender rather than risk losing him on a free transfer next year.Koulibaly has reportedly decided to join the Premier League giants, despite Barcelona's request. Thomas Tuchel's side have been desperate to reinforce their defense. Centre-backs Antonio Rudiger and Andreas Christensen left the club last month after the expiration of their contracts, thereby leaving a massive hole in the Blues' defense.The Senegal international is expected to form a formidable partnership with Brazilian defender Thiago Silva in the Blues' backline next season.Fabrizio Romano@FabrizioRomanoKalidou Koulibaly to Chelsea, here we go! Full agreement in place for €40m fee add-ons completed, bid accepted. Napoli are checking the documents then it will be official. #CFCKoulibaly will sign long-term deal for €10m net salary per season. First centre back, signed.18050427823Kalidou Koulibaly to Chelsea, here we go! Full agreement in place for €40m fee add-ons completed, bid accepted. Napoli are checking the documents then it will be official. 🚨🔵 #CFCKoulibaly will sign long-term deal for €10m net salary per season. First centre back, signed. https://t.co/Flr0XSN7wuBarcelona and Chelsea could be set to compete for another defenderSevilla FC v Granada CF - La Liga SantanderAs per The Express, Barcelona and Chelsea look set to battle it out for the signature of Sevilla defender Jules Kounde. The Frenchman has been a long-term target for Chelsea but has also attracted interest from the La Liga giants this summer. As per The Sun, the Blues have been unable to reach an agreement with Sevilla over the transfer fee for the 23-year-old.Barça Universal@BarcaUniversalJules Koundé looks increasingly likely to be heading to Barcelona, who could very well send Memphis Depay to Sevilla as part of the move.— @GraemeBailey1636108Jules Koundé looks increasingly likely to be heading to Barcelona, who could very well send Memphis Depay to Sevilla as part of the move.— @GraemeBailey https://t.co/BaIaMiXWCVBarcelona are believed to be willing to offer Dutch forward Memphis Depay plus cash to Sevilla in exchange for Jules Kounde. Xavi's side will be determined to beat Chelsea to Kounde's signature after losing out to the Blues in the battle for Kalidou Koulibaly's signature.