Not yet mortally wounded, André Villas-Boas limps on with his disjointed and disgruntled band of Chelsea players to Napoli in the Champions League on Tuesday night.

That test in a last-16, first-leg Champions League encounter follows this dire FA Cup showing against Birmingham. The chants of "You're getting sacked in the morning" from the wags in the travelling crowd found a barbed echo from the Chelsea fans, who informed their beleaguered manager he should depart now for the good of their team, and then booed when Juan Mata, who had had a penalty saved, was the player Frank Lampard replaced late on.

Villas-Boas, to his credit, did not shy away from questions about the performance and applauded a fine display from Chris Hughton's team. "No, it was not good enough, for sure it wasn't," the Chelsea manager said. "But we take the game to St Andrew's [for the replay] – a difficult game and Birmingham are undefeated in the league there – and I am sure that there we'll put on a more decent challenge.

"[In] the first half there were a lot of opportunities for us, and [it was] better in the second half, but not enough to win the game. So it is never satisfying when you draw at home to a Championship team."

With Chelsea's perpetual warrior John Terry injured (he is doubtful for Napoli, along with Ashley Cole) they lacked a spikiness that only Villas-Boas displayed when after the match he was asked about a television report that Didier Drogba had given his troops an ad hoc half-time team talk in the tunnel.

The response of the Portuguese, who had removed the now perennially disappointing Fernando Torres at the break, came laced in sarcasm. "Yeah, right, fantastic, of course," he said. "Because he has to do team talks, it's up to him. It's ridiculous. Which channel is it?"

When informed it was ESPN, he said: "It makes no sense. It's a pity because I just gave an interview to ESPN and I'm sure I wouldn't have done it if I knew that was the case."

After to the 2-0 loss at Everton, Villas-Boas had spoken on the need to find a positive response. Asked why it had not happened, he said: "There was a level of anxiety that we suffered first which didn't help. But the team commitment and the response was there straight after we suffered the setback. In the end, if the penalty goes in it's a 1-1 a little bit earlier [than the second-half equaliser] and gives you more time to find a winner. But with the game 1-0 it took us too much time to score the leveller."

Before the two first-half minutes that had threatened to consign Villas-Boas to an embarrassing footnote in this club's history even before the trip to Italy, there was a sign of how Chelsea would go behind. This involved David Luiz, the calamity of a central defender the manager continues to favour. Jordon Mutch's corner was floated in from the left and when the Brazilian fashioned a header it did not go safe but hit David Murphy, before bouncing out for the goal-kick.

Fortune now turned against the man with the fuzzy hair and his colleagues. From a further Mutch corner from the left, David Luiz this time missed the first header, along with Raul Meireles, and the ball was allowed to bounce twice in the area – sacrilege even in park football. Curtis Davies then missed an overhead kick, Branislav Ivanovic became the second Chelsea man to suffer a clearance failure, and Murphy, from close range, smashed home.

As the Bridge sucked in a collective breath Villas-Boas stood transfixed on the touchline. Then, he tried to get the attention of Mata, who had moved to the centre-spot for the restart. But as the City fans celebrated, the Portuguese's two-fingered whistle at the Spaniard was lost in the uproar.

When Ramires won a penalty moments later after Wade Elliot had needlessly brought him down, near-instant redemption beckoned. But although Mata's effort was struck well Colin Doyle palmed the ball on to his right post. Chelsea walked off to jeers at half-time and Villas-Boas was required to act. On came Drogba and off came Chelsea's £50m striker Torres.

"It was a decision that we had to make," Villas-Boas said. "We were going much more direct, based on the running of the game we wanted to up the tempo [so] Didier could act as a target man. I'm sure he [Torres] didn't take it lightly but its a decision for the team."

Hughton, operating on an extremely threadbare shoestring at a financially stricken Birmingham, and his players deserve all the praise they will get for being faster, stronger and sharper throughout. The visitors' manager said: "I'm delighted not so much with the result but the performance. I thought that we came here with a shape, I thought we were very disciplined with how we played. But you've also got to have your periods of the game where you've got to keep hold of the ball and pose a threat yourself.

"I thought over the 90 minutes we were able to do that. You have to say that was our best performance of the season, coming here at a Premier League outfit with the quality they've got."

After the break Chelsea did improve. Daniel Sturridge's header from an Ivanovic cross was this game's classiest moment. But for Villas-Boas, booed at half-time and at the end, concern continues to pile up.