Birmingham closed the gap to the Sky Bet Championship play-offs and piled the misery on struggling Bolton during a 1-0 win at St Andrews on Tuesday evening.
Clayton Donaldson's first-half strike settled a poor game as Gary Rowett's side went within three points of the top six after ending a three-game winless run ahead of Saturday's trip to QPR.
Bolton are seven points from safety although a £7.5million takeover headed by former striker Dean Holdsworth - who watched from the stands - has been agreed.
It will at least ease fears for their future but their outlook in the Championship looks bleak.
Boss Neil Lennon also left out six-goal top scorer Gary Madine after a alleged row and the Trotters never looked like scoring.
Birmingham struggled to create as well but at least took their chance when it came in the 29th minute during an instantly forgettable game.
Donaldson had been starved of service but Diego Fabbrini, who had been targeted by several robust Bolton challenges, finally wriggled free on the left.
He jinked to the byline and crossed for Donaldson to flick a neat finish beyond Paul Rachubka from six-yards. It was the striker's seventh goal of the season but owed much to the efforts of Fabbrini.
The midfielder's touch and quality were out of keeping in a scrappy game and showed why Blues forked out £1.5million to sign him from Watford in January - their biggest outlay for five years.
Bolton responded and Rob Holding headed over but there was little Lennon's side could do. Without Madine there was no focal point and Tomasz Kuszczak enjoyed a comfortable evening.
Opposite number Rachubka was rarely called on either but stopped substitute David Cotterill making it 2-0 after 73 minutes with a smart near-post save.
The ex-Manchester United trainee then saved Jon Toral's curling effort with nine minutes remaining and Donaldson missed the chance to double Birmingham's lead in injury time when he hooked over.