Andre Villas-Boas admits his insistence he was at Chelsea for the long haul would carry more weight if publicly backed by the club's hierarchy.

Blues boss Villas-Boas was once again bombarded by questions about his future ahead of Tuesday night's Champions League last-16 clash at Napoli.

The 34-year-old reiterated he was confident Chelsea owner Roman Abramovich would not sack him should he fail to reach the quarter-finals and that his three-year project to revamp the squad had the Russian billionaire's "full" backing.

Villas-Boas claimed on Thursday that he did not want a vote of confidence from Abramovich, joking that would mean "the end".

But he suggested on Monday he was beginning to sound like a broken record in his claims of unequivocal backing and it might be better if someone at the top explained they were finally going to allow a manager to see things through.

In front of watching chairman Bruce Buck and chief executive Ron Gourlay, Villas-Boas said: "You have to understand that this club, from 2004 up to now, has made a dramatic change for the best in terms of their past.

"It's the richest part of Chelsea's history, full of trophies and success, and you want to perpetuate that into the future.

"To do that, you have to sometimes make changes because you cannot sustain the same habits that you had in 2004, when this environment and team was created to make a winning team.

"These words would be more valuable coming from the top. I cannot keep saying them but, as the voice of the club, I will continue to perpetuate this message because this is what we believe in."

Villas-Boas, who has overseen what is currently the club's worst season of the Abramovich era, admitted speculation over his future was inevitable based on the Russian's previous habit of firing managers.

He said: "In terms of the results this year, the speculation is normal given the cultural past of this football club, but you have to understand that there's a different perspective now."

The Portuguese added: "I'm really confident about next year.

"That doesn't take any responsibility for what's happening now, but we had a three-year project to change not only the team, but the culture and structure of the club.

"There's a lot we needed to do, a lot of plans, so that's why I'm excited about the future. Having said that, we have to build a team to win trophies from the start.

"With that in mind, the fact that we're no longer in the Carling Cup and don't have a chance to win the (Barclays Premier League) title is a shame.

"But we are still confident we can do well in the Champions League and the FA Cup."

Asked if he had inherited an ageing Chelsea side at just the wrong time, he said: "I wouldn't have moved if I didn't feel confident I could take the challenge through.

"I was fully motivated taking on a massive job like this one and still am."

Motivating a side who have gone four games without a victory and have won just four of their last 13 matches is the big challenge, starting at the San Paolo stadium in tomorrow's last 16 first-leg tie.

Napoli have all the tools necessary to pile on the misery for Chelsea but Villas-Boas said: "Whatever happens here tomorrow will not be decisive, yet, for the running of the tie.

"Stamford Bridge, as you know, is a great stadium for European nights, which is why we wanted to finish first in the group to get the second leg at home and get a positive result."

He added: "But we have to be conscious of Napoli's strengths at the San Paolo, a team that has been built up with Europa League qualification last year and now have done very well in the Champions League.

"Tomorrow is all about awareness of Napoli's strengths and, hopefully, to bring a positive result back to Stamford Bridge."