Daniel Sturridge's 62nd minute header spared Chelsea from a humiliating FA Cup exit at the hands of Championship side Birmingham but Saturday's unconvincing 1-1 draw will do little to ease the pressure on Andre Villas-Boas.
The home side recovered after falling behind to David Murphy's first half goal to earn a fifth round replay.
But the chorus of boos as the players left the Stamford Bridge pitch confirmed this had been another sub-standard display from Villas-Boas's side.
Birmingham fully deserved the opportunity to take this tie back to St Andrew's where they will justifiably believe they have a good opportunity of reaching the quarter-finals.
For Villas-Boas, though, there was no resolution to the problems that have dogged Chelsea's season.
The Chelsea manager was anxious for his side to produce a positive performance after another troubled week at Stamford Bridge during which he admitted he did not have the full support of all of his squad.
But there was little to cheer the young Portuguese manager during a dismal first half display that hit rock bottom when Murphy put the visitors ahead in the 20th minute.
The Championship side had started the game confidently, matching Chelsea in midfield and quickly stifling any early home attacks.
At the same time Chelsea's defence once again looked shaky and there was a sign of what was to come when Jordan Mutch swung in a left wing corner.
The cross was met with an unconvincing header by Chelsea centre back David Luiz who was relieved to see his attempted near post clearance bounce off the back of Murphy and to safety.
But there was no such reprieve for Villas-Boas's side in the 20th minute when a corner flew across a crowded six-yard box before Murphy lashed home from close range.
It was an ugly goal to concede, but in keeping with too much of Chelsea's campaign.
The damage inflicted, however, appeared to be limited when the home team was handed the chance to level a minute later after Wade Elliott tripped Ramires and referee Martin Atkinson pointed immediately to the penalty spot.
Juan Mata lined up to take the spot-kick in the absence of Didier Drogba and Frank Lampard but sent a tame left foot effort too close to keeper Colin Doyle who turned the ball onto the post and wide.
The miss summed up Chelsea's troubles and while Sturridge came close with a dipping volley towards the end of the first half, they rarely looked likely to equalise.
Fernando Torres had been particularly ineffective and Villas-Boas responded by replacing the Spain forward with Drogba at half time.
The manager had planned to ease the Ivorian back into action following Drogba's return from the African Cup of Nations but with Chelsea's season on the point of taking another dive, decided he couldn't afford to wait.
Drogba's arrival did little to swing the balance of the game, though, and Birmingham could have doubled their lead had Nathan Redmond taken more care with a 56th minute shot.
Then six minutes later Chelsea finally created the opening that allowed them to level and provided relief for Villas-Boas.
Branislav Ivanovic was his side's best outlet on the right and the full back got forward to deliver a cross towards Sturridge who directed an excellent header beyond Doyle and inside the far post.
The equaliser eased the pressure but Chelsea were unable to develop the momentum that would have allowed them to go on and win the tie.
Raul Meireles came close when his deflected shot flew narrowly over but Birmingham maintained a threat at the other end and Jordan Mutch's free kick forced a hurried save out of Petr Cech.