Villas-Boas, whose side slipped out of the Premier League top four after a fourth game without a win, was even goaded by his own fans during the 2-0 loss at
Visiting supporters reacted with chants of, 'You don't know what you're doing' when the Portuguese substituted
Villas-Boas, whose predecessor Carlo Ancelotti was sacked at the same ground last year, said: "I think today was one of our worst games of the season, if not the worst.
"In our performance today we are short of anything positive.
"It is a difficult day for us, we take out a lot of negatives from this game."
Speculation over Villas-Boas' future has increased in recent days with Chelsea owner
Villas-Boas claims that did not affect the performance.
"You don't expect any effects from that," he said.
The Portuguese was also unmoved by the negative chants against him and claimed he could understand some of the frustration.
He said: "It is part of the job. At the moment we are sitting fifth in the league and it is not enough for us."
Everton took the lead after just five minutes when
Villas-Boas said: "We suffered very early in the game. We then had the control of possession until the end of the first half but couldn't create enough chances.
"In the second half the game was divided between the two teams and we had no clarity.
"We were not able to create chances. In the end that lack of clarity punished us."
The game was also another dismal one for striker
The Spaniard's place could now be under threat with Didier Drogba soon to return from the African Cup of Nations but Villas-Boas retains faith in him.
He said: "He is trying a lot to get his chances and to shoot at goal.
"Whatever time it takes, we will continue to pursue his confidence and full form until he eventually finds the back of the net."
Everton's victory was its third in successive seasons over Chelsea at home and maintained its recent revival.
"There were good parts of the performance as well but the strange thing is I think we can play much better.
"I think we will play better once we get more confidence as the wins take us a long.
"We got off to a great start with an early goal, which gave us something to hang on to, but we wanted it.
"We had to ride our luck on a couple of occasions but in the second half we didn't look like we were going to concede."
Moyes also hailed Pienaar, who is back at the club on loan after a year at Tottenham Hotspur.
He said: "He got clapped by everyone at the end, some of the stuff he did was terrific.
"I said to him at the end it was like he had never been away. Sometimes clubs just fit players and maybe that is the case. Maybe this just suits him."
Chelsea will assess an injury to England defender
The left-back limped off after a challenge by
Chelsea's England players will leave the post-season