Jose Mourinho's men sit top of the league, but were held to a 1-1 draw by title rivals Manchester City at Stamford Bridge last weekend.
Villa, meanwhile, are without a win in eight league matches, having scored just once during that run, with their total of 11 in 23 Premier League games comfortably the worst in the division.
"We know that Aston Villa, especially at home, will be a very difficult team to play against," he said. "But we have to win. We have to stay in the first position and we will do everything we can to win.
"I repeat, we know that they are good, but we want to stay with a minimum five-point lead against City."
Paul Lambert has maintained a positive outlook throughout his side's poor run of form, but will not welcome the visit of Chelsea a week after being thumped 5-0 at Arsenal.
That record is in stark contrast to his tally of 29 goals in 60 outings during his first two seasons at Villa Park, but Lambert is careful not to put too much pressure on the forward.
"If I had Christian Benteke right on his game, performing when back from injury, I'm pretty sure I'd have a long list of clubs knocking down the door for him," said Lambert.
"He's had a dip in form, he's human like everyone else. We can't rest everything on his shoulders.
"We're working hard to get him back to what we know he can do. It's something we have to get him through.
"You don't have the talent he's got and fall that far. Everyone has dips in form, it's more noticeable in him, everyone alludes to what he did in his first year.
"It's something we're working hard on to get him back to his best."
