The Portuguese coach took the blame for the Blues’ 3-1 defeat against Napoli in the Champions League on Tuesday night, after leaving key figures such as Ashley Cole and Michael Essien on the bench.
Villas-Boas insisted he has faith in David Luiz and Gary Cahill as a centre-back pairing, but insisted that successful defensive partnerships do not blossom overnight.
The 34-year-old coach told reporters on Friday: “At the moment we have a new partnership that we are trying to fine-tune to be more stable at the back, like we were in January.
“Both of them are very extrovert. Gary speaks a lot, organises a lot. It is not about communication.
“It just takes time, it's a new partnership and you have to get used to the person next to you.
“I am happy with Gary. He has been excellent in the games he has played.”
Both full-back slots in the Chelsea team have also been chopping and changing over the past month, and Cahill believes it will take time for the defence to adjust.
“There have been changes made so it's not something that will click right in to place straight away,” the England international told the club’s official website.
“It's different. The full-backs have changed so I'm not going to lie and say it's fantastically easy.
“We have had some sticky results of late and I have been plonked straight in the middle of it all so it's been difficult, but the more work we do on the training ground the better it will be.”
If picked, Cahill will face the club he left a little over a month ago, Bolton Wanderers, this weekend as the side’s face each other at Stamford Bridge.
The former Trotter revealed: “Training has been really sharp. The lads got back to work really well.
“We have to be determined to bounce back with a win. Saturday is a big day for us and when you have results like [the one in Naples] sometimes the best thing you can hope for is fixture straight after.”
Chelsea beat Bolton 5-1 in the reverse fixture last October, but that was during a period when the west London club were still considered to be title contenders - a moniker that no longer applies.
“That was maybe our strongest period of the season,” Villas-Boas stressed. “The first three or four months were the best. Now we are colliding with maybe our worst period of the season.
“In October, Bolton's motivation was a little bit down due to the results they were having but they have turned it around a bit.
“I think it will be a difficult game now but we have this willingness to turn things around and hopefully we will win against Bolton.”