NOTTINGHAM Forest's failure to land Chris Burke in the transfer window returned to haunt them in the most painful fashion, as the winger scored twice to secure a 2-1 win for the home side.
Alex McLeish's first return to St Andrews might have ended with a more positive result, if not for a string of saves made by England keeper Jack Butland.
But it proved to be Burke's contribution that was equally decisive, as the winger – the subject of a failed £500k bid from Forest on deadline day – netted either side of half time to condemn Forest to defeat.
Billy Sharp netted a penalty in injury time for the Reds, but it was not enough to help them avoid defeat.
It will have been a particularly bitter pill to swallow for McLeish, who saw Forest fail to land any of the three major targets they had craved, with a bid for Stephen Ward, the Wolves defender, also rejected and a move for George Boyd collapsing over a failed eye examination.
Manager McLeish made four changes to the team that had been humbled 3-0 at home by Watford last weekend.
Dan Harding slotted in at left back, with Greg Halford moving into the centre of defence in place of Elliott Ward, who dropped to the bench. In midfield, Guy Moussi added a little physical strength, in place of Simon Gillett and Andy Reid was brought in to replace Simon Cox.
And, finally, Darius Henderson was given his first start for Forest, coming in to the side in place of Dexter Blackstock, alongside Billy Sharp.
Khalid Al Rashidi, the Kuwaiti international keeper who arrived last week, was included on the bench.
It was Birmingham stopper Jack Butland who had to make the first meaningful save of the game, in the third minute, following a neat bit of Forest play.
Henderson headed the ball down to the on-rushing Cohen, he slotted it in to the feet of Sharp and the striker laid a one-two back into Cohen's stride, with the midfielder flashing a right-footed shot across the face of goal and forcing Butland to plunge low to his right to save.
Burke, one of Forest's targets in the January window, was included in the starting line-up for the home side and ran at Harding early on, but was fended off strongly by the Reds' left back.
Marlon King, the former Forest striker, won a corner when his turn and shot was deflected off Danny Collins, who was marking him tightly. While Burke caused danger when he did beat Harding at the second attempt, with Collins forced to make an important clearance after the winger had flashed a cross into the centre.
It was the hold-up play of Henderson that was to carve out another chance for Forest however, as he fed Sharp in space on the right. The striker then showed quick feet to engineer a shooting chance, which he lifted a few feet over the bar.
Darlow produced an outstanding save to push a Davies header around the foot of the post.
And, following a sloppy pass from Moussi in midfield, King found himself clean through on goal – forcing Darlow to made another brilliant save with his outstretched boot with a low shot – and the keeper will not have minded being robbed of the credit when referee Deadman awarded a goal kick.
When Sharp turned brilliantly on the edge of the box, it looked as though the striker had been fouled by Davies. But play was allowed to continue and Paul Robinson did brilliantly to clear when Sharp fired a cross-shot towards the far post, where Cohen was poised to pounce.
Another good move from Forest culminated in Henderson feeding Reid in space down the left, from where the winger delivered a lovely cross into the centre. Sharp connected sweetly with a glancing header – but not sweetly enough as his effort fizzed inches the wrong side of the post.
Butland had to demonstrate his England credentials – and his reactions – as Halford attacked a Reid kick powerfully at the far post, with the keeper stretching out a hand to swat the ball away.
But, in first half injury time, it was to be Burke who proved his worth, as he put the home side ahead with a spectacular goal. The winger cut in from the right side before letting fly from 22-yards with his left foot with a dipping shot that bounced into the back of the net off the underside of the bar.
Halford had an early chance to pull Forest level after the break, but he failed to hit the target with a free header, to his obvious frustration.
But King could also have extended Birmingham's advantage after finding half a yard of space to sprint into the box and fire an angled shot a few feet wide of the far post.
A clever ball, across goal, from Sharp saw Henderson pounce with a header from six yards, but Butland was equal to it.
Birmingham had brought on Nathan Redmond eight minutes into the second half and Forest made a change of their own shortly after, with Radi Majewski replacing Moussi.
Morgaro Gomis was the first player to be booked, for a foul on Lansbury, with the Birmingham man sliding in late to leave the midfielder in a heap. The Birmingham player seemed to come off worse, however, as he had to be substituted within three minutes, with an injury.
Sharp did well when collecting the ball with his back to goal, but a deflection took the pace off his shot after he had turned smartly and left Butland with an easy save.
Reid then delivered a fizzing cross that flew right across the face of goal, with Henderson just a yard short of connecting at the far post.
But it was Birmingham who carved out a clear opening, as a slip from Collins allowed Wes Thomas to sprint through on goal, only for him to lift his shot high and wide of the target with only Darlow to beat.
Butland made a world class save to thwart Forest, after Majewski and Harding had combined to give Cohen the chance to shot, with the keeper getting across brilliantly to push the shot away.
Birmingham broke quickly from the resulting corner, with Thomas again angling into the Forest box, but again firing off target when he might have done better.
He was quickly replaced by Birmingham, who brought on Nikola Zigic, while Forest also pepped up their attack with Simon Cox coming on for Henderson.
With ten minutes left, Birmingham took a firm hold of the game as Burke struck for a second time. It was substitute winger Nathan Redmond who made the goal, as he beat Jara down the left, before slotting the ball toward the far post where Burke was arriving to provide a simple, forceful finish, in the form of a low shot that gave Darlow no chance.
Sharp had the goal in his sights with five minutes to go, following a neat build-up from the visitors – but Butland denied him again, with a smart, sliding save.
Sharp did have the ball in the net in the 93rd minute, as he netted from the spot after being fouled by Davies. But Birmingham held on for victory.
Birmingham: Butland, Caldwell, Davies, Burke, King, Gomis (Reilly 64), Elliott, Thomas (Zigic 72), Caddis, Hall (Redmond 53), Robinson. Subs: Doyle, Mullins, Lovenkrands, Hancox.
Forest: Darlow, Jara, Collins, Halford, Harding, Cohen (Blackstock 83), Moussi (Majewski 56), Lansbury, Reid, Henderson (Cox 71), Sharp. Subs: Al Rashidi, Gillett, McGugan, Ward.
Attendance: 17,738 (1,963 away)
Referee: Darren Deadman