"It was not good enough," lamented the Portuguese aft his side could only draw 1-1 against Championship Birmingham City at Stamford Bridge this afternoon.
"At St Andrews ( for the replay) they are undefeated so the match will be even more of a decent challenge.
"I am not satisfied. We are experiencing a high level of anxiety, and if the penalty had gone in, we would have had more time to get the winner.
"We managed to create some chances but not enough." Asked about his misfiring forward, Fernando Torres - Villas-Boas explained his substitution.
"We wanted to up the tempo," he said.
"I'm sure Fernando is not happy - he did not come back onto the bench but he watched the game.
"Torres has a super talent and when the team wins, he will get more confidence." Speaking about his own future, he said: "It's not up to me if I'm the manager after the Napoli games."
What Chelsea need is a win - this draw was their fourth game since they last tasted victory - a 1-0 win against QPR in the last round of the FA cup.
"We need to win," he said.
"We need to give that extra push mentality when things are not gong well, but we will now focus on the Napoli game - we are ready for any challenge."
That challenge will be tested to the hilt on Tuesday when the Blues travel to Italy to face Napoli.
Struggling to make that game is captain John Terry. Villas-Boas explained: "Terry and Ashley Cole have a chance to play. Ashley is training tomorrow, but JT is doubtful," he added.
"Terry will travel, he wants to play, but is not fit enough. For instance, JT trained 100 per cent with us two days ago, then the following day he was unable to train."
Terry might not have been able to influence the game on the pitch but apparently the skipper went to see the referee Matin Atkinson at half-time complaining to him about Birmingham's time-wasting tactics.
"I'm not sure if Terry went into his room," said Villas-Boas, but it was about time-wasting." Villas-Boas also scotched TV suggestions that Didier Drogba gave a half-time team talk in the tunnel.
"That's just ridiculous," he said. "It's not true."