An npower Championship play-off final spot at Wembley is still very much in reach for Blues after a narrow defeat at Blackpool.
The Tangerines scored the only goal of the game on the stroke of half-time through a Curtis Davies own goal.
But Marlon King was agonisingly close to finding an equaliser in stoppage time, when clipping the outside of the post from a few yards out.
An electric atmosphere at Bloomfield Road was complimented by a breathtakingly open first 20 minutes, with Blues enjoying the better opportunities aside from Matt Phillips' finish being ruled out for offside.
Not to be intimidated by a strong starting Blackpool, Davies ventured up the opposite end of the pitch and headed Wade Elliott's cross narrowly wide of Matthew Gilks' left post.
And after a couple of Blackpool half-chances, King attempted an outrageous overhead kick that missed by inches.
Guirane N'Daw also produced an equally ambitious effort in the 19th minute when trying to catch Gilks off his line from 45-yards, but the Senegalese's lob was always drifting wide.
The 'Pool grew in confidence as the half wore on during lengthy spells of possession. Angel and former Blues midfielder Barry Ferguson both went extremely close from long range, while Doyle tipped Stephen Dobbie's strike wide.
But for all of the hosts' dominance, King clipped the crossbar from Burke's lay-off to almost make the Seasiders pay for their inability to break the deadlock. However, moments before the interval, Ian Holloway's men inched ahead as Ince's pot-shot deflected off an unlucky Davies to leave Doyle stranded.
Both teams looked surprisingly nervous in the early exchanges of the second-half, although Blackpool nearly doubled their advantage just before the hour mark through Gary Taylor-Fletcher.
The former Huddersfield Town player looked set to score but Davies made an excellent last-ditch block, then Dobbie fired over from close range shortly afterwards.
Roared on by a strong travelling contingent, Birmingham did their best to get back into the game but they found it increasingly hard going, which prompted Chris Hughton to make a defensive change in the form of Jonathan Spector replacing Nathan Redmond.
And they almost slipped further behind on 77 minutes courtesy of Kevin Phillips, only for his header to be deemed offside. King thought he'd grabbed a dramatic leveller in injury time, though, the forward could only find the post from Jordon Mutch's through ball.
Nevertheless, the tie is delicately poised as the Seasiders travel to St. Andrew's for the second leg on Wednesday night (7.45pm kick-off).
Blackpool: Matthew Gilks, Stephen Crainey, Neal Eardley, Ian Evatt, Stephen Dobbie (Kevin Phillips 75), Gary Taylor-Fletcher (Nouha Dicko 75), Alex Baptiste, Barry Ferguson (C), Matt Phillips, Angel, Thomas Ince.
Subs: Keith Southern, Mark Halstead, Bob Harris.
Goals: Davies (OG, 44)
Blues: Colin Doyle, Peter Ramage, Curtis Davies (C), Pablo Ibanez, David Murphy, Chris Burke, Guirane N'Daw, Jordon Mutch, Wade Elliott, Nathan Redmond (Jonathan Spector 74), Marlon King.
Subs: Jack Butland, Andros Townsend, Adam Rooney, Nikola Zigic.
Referee: M. Halsey
Attendance: 13, 832