Birmingham climbed out of the bottom three in the Premiership with a crucial win which dented Bolton's hopes of securing a European spot.
Jarosik powers Birmingham ahead with a stunning strike
The under-pressure Blues showed great determination and took the lead when Jiri Jarosik's trickery gave him space to arrow in a precise 20-yard shot.
Jarosik shot just wide moments later in a game of very few clear-cut chances.
Stelios Giannakopolous had Bolton's best chance but he poked his first-time shot wide from six yards.
The game started with the ball spending most of the time in the air as both teams attempted to take control.
And while the game was not one for the purists, it did convey the desperate situation Birmingham are in as well as Bolton's need for a win as they chase a European spot.
The home side suffered an early setback when the injured Stephen Clemence had to be replaced by Stan Lazaridis.
Bolton's best chances inevitably came from the aerial route and striker Kevin Davies headed over from eight yards while Stelios glanced an effort wide.
The Blues were forced into another substitution when injured midfielder Nicky Butt was replaced by Mikael Forssell, who quickly made an impact by shooting just over from 25 yards.
Blues boss Steve Bruce looked nervous as he stood in the dug-out prior to kick-off but he was given something to celebrate after 37 minutes.
Jarosik deservedly put ahead Birmingham ahead with his left-foot strike past the despairing dive of keeper Jussi Jaaskalainen.
The Czech Republic midfielder quickly had the chance to double his side's lead but this time his rising left-foot strike went the wrong side of the post.
The goal forced Bolton out of their shell and Kevin Nolan had a chance to equalise on the stroke of half-time only for his side-footed shot to be saved.
Bolton failed to exert a sustained spell of pressue on the Blues goal as the second half wore on but in a rare chance a Stelios snapshot went wide from six yards at the far post.
But Birmingham held on to move out of the relegation zone for the first time since mid-October last year.
Birmingham manager Steve Bruce:
"All credit to the players," said Bruce, whose side recently suffered a 7-0 FA Cup defeat to Liverpool.
"A couple of weeks ago it was the worst night of your life and now it looks like a different set of lads.
"Let's hope it can give a bit of confidence to everybody and let's see if we can cling on."
Bolton boss Sam Allardyce:
"One terrific goal from Jarosik was the difference.
"It's three defeats on the trot now and we are slipping away sadly.
"The Champions League is drifting away rapidly now. This was one of the games where we were going to catch up on the other teams and we've thrown it away."
Birmingham: Maik Taylor, Tebily, Cunningham, Martin Taylor, Sadler, Pennant, Johnson, Butt (Forssell 30), Clemence (Lazaridis 8), Jarosik, Heskey, Lazaridis (Dunn 86).
Subs Not Used: Vaesen, Campbell.
Goals: Jarosik 37.
Bolton: Jaaskelainen, O'Brien (Hunt 45), Ben Haim, N'Gotty, Pedersen, Giannakopoulos, Nolan (Vaz Te 86), Faye, Okocha, Diouf (Borgetti 68), Davies.
Subs Not Used: Walker, Nakata.
Ref: C Foy (Merseyside).