Wade Elliott struck a stoppage-time equaliser for Birmingham as Charlton threw away the lead once again.
The Addicks looked set for victory when former Leicester man Yann Kermorgant headed home two minutes from time.
But former Burnley player Elliott still found time to level after meeting Chris Burke's low cross.
Charlton's late jitters
The Addicks led Sheffield Wednesday until two goals in the final six minutes allowed the Yorkshire strugglers to win 2-1 in London on 26 January. Then Crystal Palace scored two late goals in the space of four minutes to defeat Charlton 2-1 on 2 February.
It was the third straight game Charlton failed to win after leading in the closing stages while Lee Clark's Birmingham continued their recovery.
Since losing at home to Cardiff City on 1 January, the Blues are unbeaten in five Championship games.
There was little sign of the drama to come in the previous 88 minutes, which were notable only for the poor finishing of both sides on a tricky playing surface.
Burke, Elliott and Marlon King all wasted chances for the visitors.
At the other end, Blues goalkeeper Jack Butland enhanced his growing reputation to keep out Ricardo Fuller and Scott Wagstaff, while Lawrie Wilson headed another chance narrowly wide.
But just as it appeared the game would end goalless, Addicks defender Chris Solly crossed for French forward Kermorgant to head home.
Yet Charlton's celebrations were short lived, Elliott connecting with Burke's cross to equalise with virtually the last kick.
Birmingham manager Lee Clark on goalkeeper Jack Butland, who has returned on loan after signing for Stoke: "He is an exceptional talent, one of the best young talents in Europe.
"How many young lads would have turned down the opportunity to go and play for Chelsea?
"He looked at the football side of it and he wants to play and educate himself. That for me shows you what the lad is about, that's why he is going to be a top keeper.
"It won't be long before Jack is pushing Joe Hart to be the number one - and I think Joe knows that."
Charlton manager Chris Powell: "We came across a keeper who was in imperious form.
"He made some really good saves and you could see why he has gone to the Premier League.
"It's a real shame because the boys performed really well in conditions that were tough.
"We eventually got the breakthrough late in the game and were just looking to see it out in a strong way, but it hasn't happened and we were disappointed."
Live Text Commentary
Full Time The final whistle is blown by the referee.90:00 +3:33
Christopher Burke provided the assist for the goal.90:00 +3:33 Goal scored
Goal! - Wade Elliott - Charlton 1 - 1 Birmingham Wade Elliott scores a goal from close in low into the middle of the goal. Charlton 1-1 Birmingham.90:00 +1:02
Jack Butland restarts play with the free kick.90:00 +1:02 Booking
Booking Bradley Wright-Phillips goes into the referee's book for time wasting.90:00 +0:41
The offside flag is raised against Bradley Wright-Phillips.88:48 Substitution
Substitution Nikola Zigic joins the action as a substitute, replacing Callum Reilly.88:48 Substitution
Substitution (Charlton) makes a substitution, with Bradley Wright-Phillips coming on for Ricardo Fuller.88:48 Substitution
Substitution Dorian Dervite replaces Scott Wagstaff.87:28
Assist by Chris Solly.87:28 Goal scored
Goal! - Yann Kermorgant - Charlton 1 - 0 Birmingham Yann Kermorgant scores a headed goal from close range. Charlton 1-0 Birmingham.86:48
Marlon King takes a shot. Save made by Ben Hamer.86:34
Johnnie Jackson sends in a cross, save made by Jack Butland.85:29
Headed effort from deep inside the area by Yann Kermorgant misses to the right of the goal.83:58
Ben Hamer takes the free kick.83:58 Booking
Booking Callum Reilly receives a yellow card.83:43
Unfair challenge on Dale Stephens by Callum Reilly results in a free kick.83:07
Unfair challenge on Jack Butland by Chris Solly results in a free kick. Jack Butland restarts play with the free kick.81:28
Free kick awarded for an unfair challenge on Callum Reilly by Dale Stephens. Marlon King fires a strike on goal direct from the free kick, save by Ben Hamer.80:23
Scott Wagstaff takes a shot. Save made by Jack Butland.
Outswinging corner taken from the right by-line by Paul Robinson, Steven Caldwell takes a shot. Save by Ben Hamer.78:25
Corner from the left by-line taken by Wade Elliott, Ricardo Fuller manages to make a clearance.77:12
Free kick awarded for a foul by Danny Green on Steven Caldwell. Free kick taken by Jack Butland.75:42
Unfair challenge on Paul Robinson by Michael Morrison results in a free kick. Jack Butland takes the free kick.75:13
Corner taken by Danny Green from the right by-line.74:00
Unfair challenge on Callum Reilly by Ricardo Fuller results in a free kick. Jack Butland restarts play with the free kick.73:28
Danny Green takes a shot. Callum Reilly gets a block in.72:34 Substitution
Substitution Robert Hall goes off and Nathan Redmond comes on.71:41
Marlon King challenges Michael Morrison unfairly and gives away a free kick. Ben Hamer takes the free kick.70:26 Substitution
Substitution (Charlton) makes a substitution, with Danny Green coming on for Lawrie Wilson.69:55
Effort on goal by Callum Reilly from long range goes over the crossbar.67:09
Jack Butland restarts play with the free kick.67:09 Substitution
Substitution Wes Thomas is brought on as a substitute for Morgaro Gomis.67:09
The assistant referee flags for offside against Ricardo Fuller.66:32
Scott Wagstaff takes a shot. Save by Jack Butland.65:52
Robert Hall has an effort at goal from long range that goes wide left.63:47
The assistant referee flags for offside against Marlon King. Free kick taken by Ben Hamer.62:33
Marlon King has an effort at goal from outside the penalty box which goes wide right of the target.61:22
A cross is delivered by Lawrie Wilson, clearance made by Callum Reilly.61:06
The ball is delivered by Robert Hall, Michael Morrison manages to make a clearance.59:56
The ball is delivered by Lawrie Wilson.59:06
Corner taken short by Johnnie Jackson.58:08
The ball is delivered by Johnnie Jackson, Cedric Evina takes a shot from close range clearing the crossbar.56:46
Shot from just outside the area by Ricardo Fuller misses to the right of the target.56:36
The ball is delivered by Dale Stephens, clearance made by Curtis Davies.55:43
Corner from left by-line taken by Dale Stephens.53:15
Marlon King takes a shot from just outside the penalty area which clears the crossbar.52:57
Lawrie Wilson sends in a cross, Callum Reilly manages to make a clearance.51:48
Robert Hall has an effort at goal from deep inside the area missing to the right of the target.50:46
The ball is swung over by Scott Wagstaff, Jack Butland makes a save.49:31
Inswinging corner taken left-footed by Robert Hall, Johnnie Jackson makes a clearance.48:36
Robert Hall takes a shot. Save by Ben Hamer.47:26
Foul by Yann Kermorgant on Steven Caldwell, free kick awarded. Jack Butland takes the free kick.46:42
Scott Wagstaff takes a shot. Morgaro Gomis manages to make a clearance. Johnnie Jackson takes a short corner.45:28
Dale Stephens takes a shot. Blocked by Steven Caldwell. Corner taken by Dale Stephens from the left by-line, save by Jack Butland.45:01
The second half has started.45:00 +1:05 Half time
Half Time It is the end of the first-half.44:32
Robert Hall fouled by Johnnie Jackson, the ref awards a free kick. Paul Robinson restarts play with the free kick.42:20
The ball is swung over by Chris Solly, Curtis Davies manages to make a clearance.40:51
Ricardo Fuller takes a shot. Blocked by Steven Caldwell.39:16
Ricardo Fuller gives away a free kick for an unfair challenge on Steven Caldwell. Morgaro Gomis takes the indirect free kick.34:27
Lawrie Wilson takes a shot. Save by Jack Butland.34:16
The ball is swung over by Marlon King, save by Ben Hamer.33:33
Free kick awarded for a foul by Scott Wagstaff on Callum Reilly. Paul Robinson restarts play with the free kick.31:32
Effort from the edge of the box by Ricardo Fuller goes wide of the left-hand post.30:15
The ball is sent over by Wade Elliott.28:09
The ball is delivered by Chris Solly, Yann Kermorgant takes a shot. Wade Elliott gets a block in. Inswinging corner taken right-footed by Dale Stephens from the left by-line to the near post, Steven Caldwell manages to make a clearance.27:27
Marlon King takes a shot. Blocked by Michael Morrison.25:41
Yann Kermorgant gives away a free kick for an unfair challenge on Steven Caldwell. Indirect free kick taken by Jack Butland.25:21
Marlon King takes a shot. Save by Ben Hamer.24:02
Scott Wagstaff fouled by Paul Caddis, the ref awards a free kick. Cedric Evina restarts play with the free kick.21:43
Cedric Evina delivers the ball, save by Jack Butland.20:49
Christopher Burke is ruled offside. Ben Hamer takes the free kick.19:25
Robert Hall crosses the ball, clearance by Leon Cort.18:01
Unfair challenge on Paul Caddis by Scott Wagstaff results in a free kick. Jack Butland restarts play with the free kick.15:07
Cedric Evina gives away a free kick for an unfair challenge on Paul Caddis. Jack Butland takes the free kick.12:43
Ricardo Fuller takes a shot. Save made by Jack Butland. Dale Stephens takes a inswinging corner from the left by-line to the near post, Ricardo Fuller produces a right-footed shot from close in which goes wide of the right-hand upright.10:57
Inswinging corner taken left-footed by Johnnie Jackson from the right by-line, save by Jack Butland.9:36
Unfair challenge on Ricardo Fuller by Paul Robinson results in a free kick. The ball is crossed by Johnnie Jackson, Dale Stephens takes a shot. Blocked by Callum Reilly. Corner taken by Johnnie Jackson, Paul Robinson makes a clearance.8:42
Wade Elliott produces a left-footed shot from just outside the area that goes harmlessly over the target.7:40
Callum Reilly challenges Chris Solly unfairly and gives away a free kick. Indirect free kick taken by Johnnie Jackson, Steven Caldwell produces a cross, clearance made by Leon Cort.6:45
Free kick awarded for a foul by Dale Stephens on Jack Butland. Free kick taken by Jack Butland.6:17
Short corner taken by Johnnie Jackson.5:26
Inswinging corner taken by Dale Stephens, clearance by Curtis Davies.4:08
Effort on goal by Christopher Burke from outside the penalty box goes harmlessly over the bar.3:20
Unfair challenge on Robert Hall by Johnnie Jackson results in a free kick. Marlon King fires a strike on goal direct from the free kick, blocked by Chris Solly.1:11
Lawrie Wilson is penalised for handball and concedes a free kick. Jack Butland takes the free kick.0:34
Centre by Christopher Burke.0:00
The ref blows the whistle to begin the match.
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