The Barclays Premier League campaign is only three months old but Villas-Boas' position has already come under scrutiny following a run of three defeats in four matches that have seen the Blues crash out of the top four.

The 34-year-old defiantly predicted billionaire owner Abramovich would not press the panic button after Sunday's defeat to Liverpool but acknowledged tonight that speculation the Russian might choose to act would only intensify if Chelsea did not bounce back soon.

Their current slump has raised fears of a repeat of last year's winter of discontent at Stamford Bridge - dubbed a "bad moment" by Villas-Boas' predecessor Carlo Ancelotti, but which proved long enough to cost the Italian his job.

Ancelotti's successor refused to shy away from the reality of his predicament ahead of tomorrow night's crunch Champions League clash at Bayer Leverkusen.

"When results like this happen, the head of the manager is called for execution," he said.

"I'm not worried by the comments.

"I want to get my team back to winning ways, and we'll try and do that against Leverkusen.

"As we enter a run of results, the negative spiral that this team went through last year, we don't want to go into a similar run of nine games.

"We can turn the results round. The emotions that these people lived last year are enough to make people to want to avoid that stigma this time."

Villas-Boas was charged by Abramovich with transforming Chelsea from a team built on power and pace to one more in the mould of Barcelona.

But while his squad appear to be getting to grips with a new way of attacking sides, they have failed spectacularly to adapt to their manager's defensive masterplan.

"I don't think any kind of answer I can give you would explain what has been happening," Villas-Boas said.

"We have set out to play in a different way.

"We have set out in every game to win. We don't speculate in games. We take the initiative in terms of ball possession. We create the most amount of opportunities. We are on the right track.

"It can take more or less time, but that's not an excuse for the results we've been having.

"The focus is on us to try and turn those results around. The more the focus is on us, the more we have to respond."

There have been reports some players are unhappy with the new approach but Villas-Boas said: "We think - me and the players - that it's the right way. They are enjoying what they're doing.

"You need results to gain this consistency and the confidence to play at this level and keep the philosophy.

"But the philosophy will be the last thing that will be changed. We are happy with the way we are playing."

Villas-Boas also insisted a change in personnel was not necessary to achieve his goal, and once again leapt to the defence of under-fire centre-half David Luiz.

"He'll evolve into one the best central defenders in the world," he said.

"You saw Gerard Pique: it didn't work for him at (Manchester) United, but he went to Barcelona and has become one of the best in the world. He was criticised at United, I'm sure, but look at him now."

He added of Luiz, who has started all of Chelsea's Champions League games this season: "For me as a manager, you have to help players evolve in one way or another."

One defender who appears not have struggled with Villas-Boas' tactics is Alex, who has played a part in all of Chelsea's five clean sheets this term.

Yet, Luiz's fellow Brazilian has only featured seven times in total.

Villas-Boas said: "There will always be more time for some than others.

"That doesn't mean we don't trust Alex. There are specific games, or games that have a different nature, and we opt for him in some situations."

Victory at the BayArena tomorrow would ease the pressure on Villas-Boas but defeat would really see the vultures begin to circle.

Three points would ensure Chelsea's progress from Champions League Group E and even one would not be a disaster.

But none would leave them needing at least a draw in their final game against Valencia to avoid crashing out of the competition.