Match Report: Charlton 0 Birmingham 2
Former Charlton goalkeeper Darren Randolph came back to haunt the Addicks with a host of saves to help Birmingham to three points at The Valley.
It meant the luckless south-east Londoners hadn't won in the league since Boxing Day and it left them third from bottom in the table.
The opening 10 minutes saw both sides tentatively their way feeling around the now notoriously boggy Charlton pitch.
Two of the four players making their home debut for Charlton - Reza Ghoochannejhad and Astrit Ajdarevic - made themselves known in the early exchanges; the former for a stumble in the box that the referee waved away, the latter for wasting two chances.
The second of those was a header unmarked in the box which bobbled to Randoph.
At the other end, Federico Macheda got clear in the box but fired wide of the near post.
Despite early profligacy the home fans were buoyed by some neat football from their side which also included first team home debuts for youth product Diego Poyet in midfield and French goalkeeper Yohann Thuram.
But on 22 minutes the Addicks were behind. Emyr Huws inswinging free-kick got the faintest of flicks from the head of the lively Macheda to direct the ball past Thuram,
It was a cruel blow for a side lacking in confidence after a run of disappointing results.
Charlton lost their rhythm momentarily and should have been two down when Chris Burke broke through the defence only for his touch desert him and Thuram was able to clear.
A smart Charlton move then nearly saw the scores level. Birmingham had Randolph to thank for a low save from Jordan Cousins after the youngster had been put through by Marvin Sordell.
Just five minutes before the break Randolph thwarted the Addicks again. This time Ajdarevic's acrobatic effort from a Cedric Evina cross was held by the Irish keeper. And then Randolph was down again to turn a deflected Johnnie Jackson shot wide.
Then in the dying embers of the first period, Iran international Ghoochannejhad was inches away from getting his head on a Cousins' cross when the goal was gaping.
Come the second-half and it was Ghoochannejhad who had the first meaningful effort. His shot was deflected high and caused Randolph to flap and grab it at the second attempt with Sordell lurking.
Minutes later the ball found Michael Morrison in space but the centre-back fired over.
For the visitors, Lee Novak's effort from the edge of the area went just wide.
But normal service was quickly resumed with Ghoochannejhad getting round Randolph but he couldn't squeeze it in from a tight angle and the ball was cleared.
And Sordell's long range effort was then saved low by Randolph, who was enjoying his return to the club where he started his career.
His opposite number Thuram was then needed to keep Charlton in the game, saving a Burke shot from close in.
But with the Addicks pushing men forward they were exposed on the break and Birmingham had their second.
Tom Adeyami ran into the heart of the Charlton defence and then teed up Manchester United loanee Macheda who slipped it past Thuram and into the net on 79m minutes to the joy of the sizeable away following.
It was so nearly three moments later but somehow Macheda couldn't get on the end of a Burke cross.
A goalmouth scramble at the other end summed up Charlton's day with the ball ultimately deflected off Morrison and over the bar.
There was just time for Ghoochannejhad to fire over in injury but by then all hope had evaporated from The Valley.
Charlton: Thuram; Wilson, Morrison, Wood, Evina; Cousins, Ajdarevic, Poyet (Parzyszek 87), Jackson (Green 71); Sordell (Church 71), Ghoochannejhad.
Subs not used: Phillips, Hughes, Nego, Lennon.
Birmingham: Randolph; Caddis, Packwood, Martin,Robinson; Lee, Huws; Burke, Adeyemi, Novak; Macheda (Lovenkrands 87).
Subs not used: Doyle, Howard, Shinnie, Brown, Rusnak, Blackett.