Chelsea must pay a world-record fee for a defender to sign Croatian World Cup star Josko Gvardiol, according to reports.

According to Sky Germany, Gvardiol, who shone at the World Cup for Croatia, has a release clause of about €110m that becomes active in 2024.

€110million (£96million) is a world-record fee for a defender, beating the £80million Manchester United paid to Leicester City to sign Harry Maguire.

RB Leipzig are increasingly confident of holding onto Gvardiol next summer as it will cost even more than his release clause to sign the defender next summer.

Chelsea have been strongly linked with the centre-back, but it looks like the Blues face a fight to bring him to west London with Leipzig keen to hold out until 2024.

Meanwhile, former Chelsea defender William Gallas believes Chelsea should have signed Josko Gvardiol last summer instead of spending more than £100million on Wesley Fofana and Kalidou Koulibaly.

Gallas fears Chelsea have missed the boat regarding a deal for the 20-year-old as several other clubs have now expressed interest in striking a deal with RB Leipzig.

Gallas has described Fofana and Koulibaly as ‘panic buys’ and believes Chelsea overpaid for the duo.

“Chelsea were linked with Gvardiol last summer and they should have got him then,” Gallas told Genting Casino. “Instead, they got Fofana and Koulibaly.

“They already have Thiago Silva and Azpi [Cesar Azpilicueta] too so it may be difficult to get Gvardiol now. At the start of the season it would have been a good move but I don’t know if it would be now.

“Chelsea panicked in the summer. They saw some players and put a lot of money towards them when for me, they did not meet their value.

“Some chairmen spend too much money when they have no idea what they are doing.”