Chelsea cannot afford to lose Willian, Eden Hazard or Thibaut Courtois, says David Luiz

David Luiz believes Chelsea cannot afford to lose "key players" Eden Hazard, Thibaut Courtois or Willian amid interest from Real Madrid and Barcelona.

Hazard has long been linked with a move to Real Madrid and his performances for Belgium at the World Cup further fuelled that speculation.

It is understood the most likely of the three players to leave would be goalkeeper Thibaut Courtois who only has a year remaining on his current deal at Stamford Bridge.

Barcelona's latest offer for Wiliian, which exceeded £55m, has been rejected by Chelsea.

Luiz has been in regular contact with his Brazilian compatriot and believes he is happy at Stamford Bridge.

"(We speak) almost every day, he loves playing for Chelsea, I don't let him go! I think he's going to stay," Luiz told Sky Sports News following Chelsea's 1-0 victory over Perth Glory on Monday.

"Seriously I'm not joking, Chelsea has to keep the best players and these three players are key players for our team so in a serious way I want them to stay.

"They are fantastic players and fantastic talents, we need the best players at Chelsea."

New Chelsea head coach Maurizio Sarri has stated he intends to speak to any players wanting to leave the club by the end of July.

Belgium internationals Hazard and Courtois have both been afforded a three-week holiday following their World Cup exploits and are not scheduled to return to Cobham until August 5 or 6.

Willian is expected back a week earlier following Brazil's exit from the World Cup on July 6 at the hands of Belgium.

Chelsea's next game is on Saturday against Inter Milan in the International Champions Cup at the Allianz Riviera in Nice.

The Blues then face Arsenal on August 1 before their season begins in earnest on August 5, when they play Manchester City in the Community Shield at Wembley.