Villas-Boas was still smarting on Tuesday afternoon at the manner of what was his first loss in charge of the Blues and his first defeat in a league game for 17 months.

Chelsea fell 2-0 behind at Old Trafford on Sunday to goals which replays showed should not have stood as both scorers had been offside, with United eventually running out 3-1 winners.

Villas-Boas revealed he had contacted referees' chief Riley about those incidents and also the decision to award Manchester United a "soft" penalty.

But he added: "Nothing is going to change regarding the performance of the referees and I'm not trying to influence decisions, just calling attention to the fact that this situation happened and it played an extremely important part in the result."

Villas-Boas also insisted he had not asked for Sunday's referee, Phil Dowd, to be withdrawn from future Chelsea matches.

"I would never do that," he said.

"The game should be human, with as many emotions as possible, and I think that the referees have a major part to play."

Poor officiating did not mask the fact that, despite dominating Sunday's game in an attacking sense, Chelsea once again looked extremely vulnerable at the back.

But Villas-Boas was adamant that was not the case, saying: "I cannot lose my time organising my defensive set plays for the referee to make a mistake like that - I'm sorry.

"You organise a team to defend a set play, to be coherent, to hold the line, and then there is a person who does not do his job.

"We had an incident like this against Sunderland the other day - offside not given.

"So it's not a question of organisation, it's not a question of defensive fragilities. It's a question of a mistake that you pay the penalty for."

Chelsea were also wasteful in front of goal, with Fernando Torres producing one of the worst misses in Premier League history.

The £50million man's open-goal gaffe has been the subject of much mirth in the past 24 hours but it was no laughing matter for his manager.

"It's nothing to joke about when you lose at Old Trafford," Villas-Boas snapped.

The Portuguese also leapt to the defence of Frank Lampard, whose half-time substitution on Sunday was seen by some as the further evidence his powers are on the wane.

Insisting his fellow 33-year-old was still one of the world's best players, Villas-Boas denied the midfielder's future lay solely in a deeper-lying role.

"You are taking the question towards an age problem or a slowing problem, with which I completely disagree," he said.

"Frank has played 90 minutes in all games before with maximum intensity, with extremely good physical stats that he has always had in his career.

"He can play in different roles because he has done it in the past, the number 10, the eight, the six."

Lampard lost his England place earlier this month, but Villas-Boas was adamant Sunday's change bore no relation, saying: "Trying to associate that with what happened with England, I would keep away from it."

Torres and Lampard look set to be rested for tomorrow's Carling Cup third-round tie against Fulham, with Villas-Boas confirming he was under orders from Roman Abramovich to blood Chelsea's youngsters in the competition this season.

Villas-Boas revealed the Blues' billionaire owner had told him to play the likes of Josh McEachran, Romelu Lukaku, Oriol Romeu and Ryan Bertrand as part of their development.

Predecessor Carlo Ancelotti appeared to be issued with the same instructions last season only for Chelsea to crash out of the competition to Newcastle.

"From what the owner has told me, it's a decision that he wants taken because he wants to promote talent as well," Villas-Boas said.

"Don't get me wrong because I think there are responsibilities for us to try to win the trophy as well."

Villas-Boas pointed out Arsenal had been "doing it for years".

"You can discuss if it has been useful or not, the situation, in terms of the talent," he said.

"I think it has been and that talent last year reached the final. They reached a couple of semi-finals as well."

He added of his own youngsters: "It's important for them to get a feeling for the competition."