The Blues boss insists there were no positives to take from Goodison Park defeat and admits it was a 'difficult day' for the Londoners who slip to fifth in the table
The home side took the lead in the opening five minutes through Steven Pienaar, making his first appearance at Goodison Park since rejoining Everton on loan.
Denis Stracqualursi then doubled the lead in the second half and Chelsea were unable to recover the deficit.
"I think today was one of our worst games of the season," Villas-Boas told reporters. "I think the worst in every sense of the word.
"Everton were fantastic today I think growing up from what they have been doing also the signings have helped them improve a lot.
"In our performance today we aren’t sure of anything positive. It’s a difficult day for us a lot of negatives to take out from this game and a lot of things to improve bearing in mind the FA Cup and Champions League."
Villas-Boas then dismissed concerns about the influence of Chelsea owner Roman Abramovich watching his side training on a number of occasions this week.
"You don’t expect any effect from that. We suffered early in the game and had the control of possession till the end of the first half but couldn’t create enough chances," he added.
"In the second half the game got divided between the two teams, very aggressive physically and we had no clarity and we weren’t able to create chances. In the end that lack of clarity punished us today."
It certainly seems that the knives are out for Villas-Boas in some quarters, with sections of the travelling crowd chanting, "You don't know what you're doing" at the Chelsea boss.
"It’s part of the job," Villas-Boas maintained. "At the moment we are sitting fifth in the league and it’s not enough for us."
Michael Essien has now started his second game in a row after last week's 3-3 draw with Premier League leaders Manchester United following his return from injury, but Villas-Boas said that the decision to substitute the midfielder was purely tactical, and that they were not changing their system purely for Fernando Torres.
"First we wanted a change of system. We wanted to put [Juan] Mata between the lines like against Manchester United so we started with that but when we suffered the second goal we wanted more upfront," he explained.
"No. [Fernando Torres] is trying a lot to get his chances and to shoot at goal. Whatever time it takes, we continue to pursue his confidence and his full form till he eventually finds the back of the net. I don’t create a system to make one player perform more."
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