The Liga giants are reported to have tabled three bids for an attacking talent they consider to be a perfect fit for their plans at Camp Nou.
Those at Stamford Bridge have stood firm so far, with new boss Maurizio Sarri reluctant to part with any prized assets.
Luiz hopes key men can be retained, with the likes of Eden Hazard and Thibaut Courtous also generating unwelcome exit talk.
"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."
Marcos Alonso is also looking for Chelsea to fend off mounting interest in their star turns.
While Barca have been sniffing around Willian, Real Madrid continue to be linked with Belgian duo Hazard and Courtois.
Alonso said of the transfer speculation which continues to rage in west London: "I am not even thinking about that.
“They are Chelsea players and I am looking forward to seeing them after their holidays.
"They are top players and very important for us.
“Every season with Chelsea, we have to fight for every competition and every game and we will go for it."
It may be that Barca have ended their interest in Willian, much to Chelsea’s relief, with a stunning move having been made for Bordeaux forward Malcom despite the Brazilian having seen a deal agreed with Roma.