Chelsea head into the weekend with a seven-point lead over Arsenal at the summit, as well as a game in hand over the chasing pack.
Rangers are two points adrift of safety having played at least a game more than most of the sides around them - Aston Villa the exception following a 3-3 draw between the sides on Tuesday.
"[This is] obviously a very important match for both teams," said Chelsea boss Jose Mourinho. "We know that, we know they want to win. Nobody is expecting an easy match.
"We have to win every game, we have to win the next game and we don't think about the points we have or the match we have in hand, we just think about the next match.
"I know QPR have played one match more than the teams they are competing with and everyone knows they need points in these remaining six matches they have, so we know it's a difficult game."
Asked whether he was expecting to be greeted by a hostile atmosphere at Loftus Road, Mourinho added: "It's what people tell me. I've never played there, so I don't know, but that's what people tell me.
"The people in the stands can play a role, but they cannot score goals."
QPR boss Chris Ramsey believes Sunday's clash is a bigger fixture for his side than it is for Chelsea, whose healthy cushion at the top of the table is in stark contrast to their London rivals' plight.
"That's a fair assessment," he remarked. "They can afford to have a blip and still win the league. We really do need to pick up every point that we can.
"It'll be a very, very tough game. Hopefully an enjoyable game for the fans, but not too enjoyable for the neutral because I hope that we can do well and collect all the points.
"But we know that any team playing Chelsea - especially in the form that they're in and in the run-in to the championship - it's going to be a very difficult game and the players are up for it."
Chelsea striker Diego Costa is expected to miss four matches after lasting just 11 minutes as a second-half substitute in last weekend's 2-1 victory over Stoke City before pulling up with yet another hamstring injury.
Cesc Fabregas will wear a mask after breaking his nose and, along with Nemanja Matic, is one booking away from a two-match ban, with Manchester United and Arsenal next up.
Eduardo Vargas (knee), Rio Ferdinand (knock), Leroy Fer (knee) and Richard Dunne (fitness) are among QPR's considerable list of absentees.
