Will Buckley’s 23rd minute goal has given Birmingham a 1-0 half-time lead over the Blues, who are up against it in the second half with Jonathan Douglas having been red-carded moments before the break.
As expected, boss Mick McCarthy reverted to the team which drew 1-1 with Preston last Saturday, having changed his entire XI for the FA Cup replay at Portsmouth on Tuesday.
New signing Kevin Foley’s international clearance came through and the full-back took a place on the Town bench, while loanee Paul Digby was included in a Championship matchday 18 for the first time.
The home side made one enforced changed from last week’s 3-0 win at Derby with Jacques Maghoma unwell. On-loan Sunderland winger Buckley came into the side for his full Birmingham debut.
After a quiet opening few minutes, the Midlanders created the first opening in the fourth minute, Buckley, often a thorn in Town’s side when a Brighton player, finding himself space 20 yards out but scraping wide.
A minute later, Stephen Gleeson, who played for Blues boss McCarthy at Wolves, scuffed another effort well past the post.
Town weren’t far away from going in front with their first chance of the game on six. Ryan Fraser laid the ball back to Kevin Bru on the left and the Mauritius international whipped over a cross which Daryl Murphy headed just over Tomasz Kuszczak’s crossbar from six yards.
Soon after, Clayton Donaldson thought he’d failed to take the chance of the game up to that point when he slid in but failed to connect with Maikel Kieftenbeld’s cross from the left but the linesman’s flag had been raised.
Murphy went close again for the Blues in the 11th minute when Bru fed the Irishman just outside the area to the left, where he flicked the ball up and smashed a strike across the face of goal.
Both sides were continuing to have chances and on 14 Jon Toral struck a powerful 25-yard effort which Blues keeper Dean Gerken did well to bat away from goal.
On 21 Birmingham defender Paul Caddis inadvertently presented the ball to Fraser on the Town left when trying to avoid conceding a corner, allowing the Scotland U21 international to whip over a cross which Freddie Sears flicked towards goal, however, Kuszczak was able to claim above his head.
Two minutes later, the visitors went in front via a goal Town will think they really ought to have prevented.
Tommy Smith’s headed clearance only reached Jonathan Grounds, who crossed from the left. The ball was turned away from goal but hit Douglas and ran to Donaldson, who hit a shot which Gerken saved superbly at point blank. However, the rebound fell to Buckley, who tapped home his first Birmingham goal from close range.
As the game moved towards the half hour mark Gleeson picked up the game’s first booking for a blatant trip on Fraser as the winger broke down the left.
After the resultant freekick had been worked down the left, the ball came out to Cole Skuse midway inside the Birmingham half but the midfielder’s shot flew well over.
Kieftenbeld went close to adding to his side’s lead on 40 when he made the most of more hesitant Town defending on the edge of the area, but the Dutchman’s shot was deflected wide.
Next it was the Blues' turn to threaten. With Kieftenbeld down injury and the home crowd calling for play to be stopped, Fraser cut in from the right and hit a powerful low shot which Kuszczak saved down to his right. Sears was first to the rebound which the Polish keeper again saved.
The ex-Colchester man got the the loose ball first again but his strike was deflected behind for a corner. From the flag-kick, Sears was just unable to get a touch to Christophe Berra’s header before Kuszczak claimed.
In first-half injury time Fraser crossed from the left and Murphy glanced a header well wide.
Seconds before the whistle Town were reduced to 10 men for the second successive game.
Douglas dived in for a ball which had run away from him midway inside the Blues half and caught Buckley with a one-footed but studs-up challenge on his shins.
Referee Michael Bull had no hesitation in issuing the 34-year-old with what looked a correct straight red card, Town’s first of their Championship campaign.
There hadn’t been much in the half as a whole with both teams having created opportunities - Town’s best was probably Murphy’s early header - and the two keepers each having made saves.
The Blues were made to pay for poor defending for the goal and having been reduced to 10 men have an uphill task to get back into the match in the second half.
Town: Gerken, Chambers (c), Smith, Berra, Knudsen, Skuse, Douglas, Bru, Fraser, Sears, Murphy. Subs: Bialkowski, Digby, Foley, Hyam, Maitland-Niles, Pitman, Varney.
Birmingham: Kuszczak, Caddis, Morrison (c), Robinson, Grounds, Gleeson, Kieftenbeld, Davis, Buckley, Toral, Donaldson. Subs: Legzdins, Vaughan, Adams, Solomon-Otabor, Spector, Lowry, Brock-Madsen. Referee: Michael Bull (Essex).