Daniel Sturridge's second-half header spared Chelsea a humiliating FA Cup fifth-round exit against Birmingham but did nothing to ease the pressure on Andre Villas-Boas.
The Chelsea manager cut a forlorn figure on the touchline as his lacklustre side left the Stamford Bridge pitch to a chorus of boos and chants of support for former manager Jose Mourinho.
Chelsea were woeful before the interval and the visitors deservedly led through David Murphy's close-range strike.
The hosts squandered a glorious chance to level when Juan Mata's penalty was well saved by Colin Doyle.
But the home side improved and earned a replay when Sturridge headed in Branislav Ivanovic's teasing cross.
Winless in four, already out of the Premier League title race and in serious danger of failing to qualify for the Champions League, Chelsea's season was already in the doldrums.
Desperately needing to make FA Cup progress before their season-defining European tie with Napoli on Tuesday was not the brave new world envisaged by owner Roman Abramovich at the start of the campaign.
DID YOU KNOW?
Chelsea have not been beaten at home in the FA Cup by lower league opposition since losing to Oxford United in 1991.
But a convincing win - and equally convincing display - could have been the precursor to better times and provided a confidence-boosting platform.
The reality, against a spirited and superbly organised Birmingham, who are now unbeaten in 14 games, was very different.
The first half was far too typical of Chelsea in the past two months - slow to start, ponderous in midfield, sloppy in defence and only a threat in attack through the searing pace of Sturridge and inventiveness of Mata.
Birmingham made the most of the Premier League side's slow start to go ahead when Murphy netted after the defence dithered following a well-worked near-post corner.
But while the noisy away Blues contingent were still taunting the home support and suggesting that Villas-Boas would be "getting sacked in the morning", Chelsea had a wonderful chance to instantly draw level.
An incisive move on the edge of the box saw Ramires wriggle free only to be felled by Wade Elliott.
Mata, who had scored in both of Chelsea's FA Cup wins this season, opted to go low but his effort was not particularly well struck and was saved by the excellent Doyle.
Sturridge then had a decent claim for a second spot-kick and the home side began to dominate possession and create chances.
David Luiz had a 25-yard free-kick pushed way by Doyle, and Sturridge was within a whisker of levelling with a vicious, dipping volley from the edge of the box.
Chelsea were vastly improved after the interval, mainly thanks to a change in formation that saw Didier Drogba replace the anonymous Fernando Torres and John Mikel Obi sacrificed in favour of Salomon Kalou.
Up until then Birmingham's packed midfield had deprived Chelsea time and space with the tireless running of striker Adam Rooney particularly inspirational.
But the home side started to dominate possession, territory and chances.
Sturridge restored parity just after the hour when his beautifully guided header, from Ivanovic's cross, nestled in the far corner.
They then went close to taking the lead, with Mata shooting wide after a controlling a long ball forward and Raul Meireles firing in a shot that took a deflection before bouncing up and over the bar.
Redmond had Birmingham's only chances after the interval, shooting over following a clever corner routine and fluffing a wonderful late opportunity as he bore down on goal.
Chelsea pressed for a late winner but had to make do with a replay at St Andrew's on Tuesday, 6 March (1945 GMT).
- 01 Cech
- 02 Ivanovic
- 04 David Luiz Booked
- 24 Cahill Booked
- 34 Bertrand
- 07 Ramires
- 12 Mikel (Kalou - 57' )
- 16 Meireles
- 09 Torres (Drogba - 46' )
- 10 Mata (Lampard - 83' )
- 23 Sturridge
- 40 Hilario
- 17 Bosingwa
- 05 Essien
- 08 Lampard
- 15 Malouda
- 11 Drogba
- 21 Kalou
- 13 Doyle
- 02 Carr (Spector - 12' )
- 03 Murphy
- 05 Pablo
- 24 Davies
- 12 Mutch Booked
- 14 Gomis
- 15 Elliott (Burke - 83' )
- 18 Fahey
- 22 Redmond
- 17 Rooney (Jervis - 71' )
- 26 Butland
- 04 Caldwell
- 23 Spector
- 07 Burke
- 35 Reilly
- 25 Asante
- 36 Jervis
Live Text Commentary
Full Time The match has reached full-time.90:00 +2:45
The offside flag is raised against Nathan Redmond. Petr Cech restarts play with the free kick.90:00 +2:19
Morgaro Gomis fouled by Ramires, the ref awards a free kick. David Murphy restarts play with the free kick.90:00 +1:40
Headed cross/shot by Jordon Mutch, save made by Petr Cech.90:00 +1:40 Booking
Booking The referee books David Luiz for unsporting behaviour.90:00 +1:30
Foul by David Luiz on Jonathan Spector, free kick awarded.90:00 +0:39
The assistant referee flags for offside against Branislav Ivanovic. Indirect free kick taken by Colin Doyle.89:08
Free kick awarded for a foul by Pablo Ibanez on Branislav Ivanovic. Didier Drogba shoots direct from the free kick.88:48
Jordon Mutch gives away a free kick for an unfair challenge on Frank Lampard. Free kick taken by Raul Meireles.87:39
Jake Jervis is caught offside. Gary Cahill restarts play with the free kick.86:45
Nathan Redmond takes a shot. Save by Petr Cech.85:06
Corner taken by Frank Lampard from the right by-line, free kick awarded for a foul by Gary Cahill on Curtis Davies. Direct free kick taken by Colin Doyle.84:31
The offside flag is raised against Daniel Sturridge. Free kick taken by Colin Doyle.83:46
Inswinging corner taken by Raul Meireles.82:11
The assistant referee flags for offside against Salomon Kalou. Colin Doyle restarts play with the free kick.82:11 Substitution
Substitution Frank Lampard comes on in place of Juan Mata.82:11 Substitution
Substitution Chris Burke comes on in place of Wade Elliott.80:30
Long range effort from Raul Meireles misses to the left of the goal.76:04
Jordon Mutch fouled by Raul Meireles, the ref awards a free kick. Jordon Mutch has an effort direct from the free kick, save by Petr Cech.72:58
Outswinging corner taken from the left by-line by Juan Mata, Morgaro Gomis manages to make a clearance.
Corner taken left-footed by Juan Mata, Raul Meireles takes a shot. Jonathan Spector gets a block in.70:24 Substitution
Substitution Jake Jervis is brought on as a substitute for Adam Rooney.69:24
Corner taken by Juan Mata from the right by-line.68:15
The referee blows for offside. Petr Cech restarts play with the free kick.66:44
Unfair challenge on Raul Meireles by Wade Elliott results in a free kick. Free kick crossed by Raul Meireles, clearance made by Colin Doyle.65:49
Curtis Davies gives away a free kick for an unfair challenge on Didier Drogba. Direct free kick taken by Raul Meireles.64:12
Free kick awarded for a foul by Morgaro Gomis on Daniel Sturridge. Juan Mata takes the free kick.63:50
Free kick awarded for an unfair challenge on Ramires by Nathan Redmond. Ramires restarts play with the free kick.62:36
Salomon Kalou has a headed effort at goal from deep inside the area missing to the left of the target.61:04
Branislav Ivanovic provided the assist for the goal.61:04 Goal scored
Goal! - Daniel Sturridge - Chelsea 1 - 1 Birmingham Daniel Sturridge finds the back of the net with a headed goal from inside the penalty box. Chelsea 1-1 Birmingham.59:53
Jordon Mutch challenges Gary Cahill unfairly and gives away a free kick. Free kick taken by Petr Cech.58:56
Juan Mata produces a right-footed shot from deep inside the penalty area which goes wide of the right-hand post.56:44 Substitution
Substitution Salomon Kalou on for Mikel.54:55
Corner taken right-footed by Jordon Mutch, Shot from deep inside the area by Nathan Redmond clears the crossbar.54:08
Jordon Mutch crosses the ball in from the free kick, Gary Cahill makes a clearance.54:08 Booking
Booking Gary Cahill goes into the referee's book for unsporting behaviour.54:01
Foul by Gary Cahill on Adam Rooney, free kick awarded.53:33
Morgaro Gomis gives away a free kick for an unfair challenge on Mikel. Mikel takes the direct free kick.52:35
Foul by Ryan Bertrand on Wade Elliott, free kick awarded. Jonathan Spector takes the direct free kick.51:39
Free kick awarded for an unfair challenge on Wade Elliott by Juan Mata. Jonathan Spector takes the free kick.50:22
Daniel Sturridge is flagged offside by the assistant referee. Indirect free kick taken by Pablo Ibanez.48:09
Adam Rooney gives away a free kick for an unfair challenge on Ramires. Direct free kick taken by Branislav Ivanovic.46:39
Ramires fouled by David Murphy, the ref awards a free kick. Free kick taken by Raul Meireles.45:39
Free kick awarded for a foul by Ramires on David Murphy. Free kick taken by Colin Doyle.45:01
The second half has started.45:01 Substitution
Substitution Fernando Torres goes off and Didier Drogba comes on.45:00 +1:19 Half time
Half Time The whistle is blown to end the first half.44:05
Juan Mata takes a shot. Save by Colin Doyle.42:41
Daniel Sturridge takes a shot. Curtis Davies gets a block in.40:31
Shot from 35 yards by Mikel went wide of the left-hand post.38:32
Daniel Sturridge has an effort at goal from outside the penalty box missing to the wide left of the goal.36:39
Free kick awarded for a foul by Jonathan Spector on Fernando Torres. Juan Mata crosses the ball in from the free kick, Pablo Ibanez makes a clearance.35:19
Nathan Redmond takes a shot. Petr Cech makes a comfortable save.34:33
Daniel Sturridge has a headed effort from close range and clears the crossbar.34:12
Corner taken by Raul Meireles from the right by-line, David Murphy makes a clearance.33:10
David Luiz produces a shot on goal direct from the free kick, save by Colin Doyle.33:10 Booking
Booking Booking for Jordon Mutch for unsporting behaviour.32:57
Free kick awarded for an unfair challenge on David Luiz by Jordon Mutch.32:31
The official flags Jordon Mutch offside. Indirect free kick taken by David Luiz.27:05
Unfair challenge on Keith Fahey by Ramires results in a free kick. Colin Doyle restarts play with the free kick.22:26 Penalty
Penalty taken by Juan Mata is saved by Colin Doyle. Chelsea 0-1 Birmingham.21:28
Penalty awarded for a foul by Wade Elliott on Ramires.19:47
Assist by Adam Rooney.19:47 Goal scored
Goal! - David Murphy - Chelsea 0 - 1 Birmingham David Murphy finds the net with a goal from inside the six-yard box to the bottom left corner of the goal. Chelsea 0-1 Birmingham.19:15
Corner taken by Jordon Mutch played to the near post,11:47 Substitution
Substitution Jonathan Spector comes on in place of Stephen Carr.10:04
Inswinging corner taken by Jordon Mutch, David Luiz makes a clearance.4:44
Foul by Ramires on Keith Fahey, free kick awarded. Direct free kick taken by Colin Doyle.0:00
The match gets underway.
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