Isaac Vassell’s goal ended Birmingham’s winless run as they clinched a 1-0 home victory against a misfiring Sheffield Wednesday.
The substitute earned caretaker manager Lee Carsley his first win in charge as the hosts won their first game in nine outings.
It failed to lift the Blues out of the Sky Bet Championship relegation zone, and they sit in the bottom three on goal difference while inconsistent Wednesday remain in mid-table.
A low-quality game looked destined to end goalless, especially when Gary Hooper’s close-range strike for Wednesday was disallowed for offside, before Vassell grabbed the 76th-minute winner.
It further boosted Birmingham, who sacked Harry Redknapp earlier this month, after Carsley had bought the club time in their search for a new boss following Saturday’s 1-1 draw at Derby.
But Birmingham initially struggled to impose themselves at home.
It was a turgid opening and it took until the 22nd minute to see a clear chance when Wednesday’s Adam Reach should have done better than to plant a free header straight at Tomasz Kuszczak.
Before then David Davis shot straight at Joe Wildsmith from distance but the hosts should have taken the lead after 29 minutes.
Wednesday failed to deal with Davis’ cross and when the ball fell to Jeremie Boga, the Chelsea loanee blazed over the bar from eight yards.
The miss underpinned the lack of quality at St Andrew’s, although Craig Gardner had to hook away a goal-bound header from Tom Lees just before the break.
Birmingham’s finishing after the re-start initially failed to improve either as Cheikh Ndoye fired over the bar from 10 yards with just Wildsmith to beat.
Wednesday then thought they had grabbed the lead after 71 minutes when Hooper tapped in Morgan Fox’s cross but it was ruled out by the linesman’s flag.
However, five minutes later Vassell’s first goal for Birmingham since his summer move from Luton won it when he fired in Jacques Maghoma’s cross at the far post.
Lucas Joao, Barry Bannan and Kieran Lee all had chances to level late on but Birmingham survived.
Birmingham City: Kuszczak, Nsue, Morrison, Dean, Colin, Davis, Gardner (Roberts 89), N’Doye, Maghoma, Jutkiewicz (Vassell 61), Boga (Gallagher 83). Subs Not Used: Grounds, Cotterill, Trueman, Gleeson.
Sheffield Wednesday: Wildsmith, Hunt, Lees, van Aken, Fox (Lucas Joao 78), Lee, Butterfield, Bannan, Reach, Hooper, Fletcher (Rhodes 62). Subs Not Used: Jones, Palmer, Dawson, Wallace, Pudil.
Referee: Stephen Martin (Staffordshire).