Maurizio Sarri believes Chelsea cannot afford to lose Eden Hazard.
Hazard's first-half wonder goal set Chelsea en route to a 2-0 Premier League win over West Ham at Stamford Bridge, with the Belgium star also bagging a late second.
West Ham's fans taunted Chelsea by singing "He's off to Madrid", with the Blues' board apparently holding out for £100million from Real to complete a transfer this summer.
Hazard's contract expires next year, and while the 28-year-old claims he is undecided on his long-term future, Chelsea boss Sarri feels the Blues must continue to fight to retain their prize asset.
Asked if Chelsea can afford to lose Hazard, Sarri replied: "From the technical point of view, no, not at the moment.
"It's impossible to find another Hazard; at the moment there isn't another Hazard. The level is so high. In the world you can't find another player like that.
"So I hope that Hazard can stay here, otherwise we have to try something different."
In the 24th minute, Hazard scored a goal of the rarest quality as he waltzed his past five West Ham players before drilling Chelsea into the lead in west London.
The former Lille playmaker then buried a second at the death as Chelsea stepped up to third in the Premier League table, although playing a game more than Champions League qualification rivals Tottenham and Arsenal.
Chelsea head coach Sarri is convinced the Blues are doing all they can to hold onto Hazard, however, he did concede the player himself will have the final say on his destination.
"I am sure the club doesn't want to sell him," Sarri said. "But of course we all have to respect his decision.
"He's in the last season of his contract. If he wants to have another experience we have to respect it but we will try in any way to convince him. But it's not easy."
When asked if Hazard has told him he wants to leave, Sarri added: "No. He told me that he has to decide."
Hazard has now equalled his best goals tally for a single season for Chelsea, scoring 19 in all competitions.
After branding his stunning opener "special", Hazard insisted he still has not made a decision over whether to join Real Madrid.
"They are wrong! I am focused on Chelsea until the end of the season," Hazard told Sky Sports, when asked about the Hammers' fans claiming he would head to Real this summer.
"I want to finish in the top four and in the Europa League. We still have a lot to do, and then we will see."
Boss Manuel Pellegrini admitted the Hammers' lacklustre first-half cost them dear at Stamford Bridge.
"When you want, you can; if you don't want, it's impossible," said Pellegrini.
"You must desire to demonstrate how you can play, which team you are. We did that in the second-half."
Unfortunately for Pellegrini, Samir Nasri picked up a calf injury while warming up at half time.
"Nasri was going to start the second-half but during the warm-up he felt a muscle injury in his calf so he was not confident to play," confirmed Pellegrini.
"We'll see how he is tomorrow."
