Blues came away from Pride Park with nothing to show for their efforts despite a brave second-half fight-back against Derby County.
Substitute Nathan Tyson struck the knockout blow with five minutes remaining to edge an enthralling encounter, which had seemed to be swinging in the visitors’ favour.
Conor Sammon gave Derby a first-half lead but the introduction of new loan signing Rob Hall sparked Blues into life after the interval.
The England youth international won a penalty – confidently converted by Marlon King – before Sammon struck again to put the Rams back in front.
But Blues rallied once more and conjured another equaliser moments later when another substitute, Peter Lovenkrands, headed Jonathan Spector’s cross into the far corner.
However, with Blues in the ascendancy, Derby snatched the points when Tyson scrambled home Michael Jacobs’ cross.
It was harsh on Blues, who dominated large parts of the second-half having spent most of the first-half on the back-foot.
With the exception of a Hayden Mullins shot which flew wide of the target, Lee Clark’s side struggled to test the Rams’ former Blues goalkeeper Adam Ledzgins in the early stages.
Derby bossed possession but they too failed to test Jack Butland in the Blues goal and Theo Robinson’s wayward effort from 25-yards summed up their frustration.
Wade Elliott failed to capitalise on Blues’ best opportunity midway through the half. The ball found its way through to the midfielder just inside the area after good link-up play between King and Ravel Morrison, but with the angle tight, Elliott could only find the side netting.
The home side seized the initiative in the 32nd minute. The dangerous Jacobs cut inside form the left and unleashed a powerful effort which Butland tipped onto the post. Unfortunately for the Blues keeper, the ball rebounded kindly for Sammon to head into the opposite corner of the net. Replays showed the striker was in an offside position when Jacobs struck the initial shot.
Blues began the second-half with renewed vigour and immediately set about finding an equaliser. It almost arrived straight away when Nikola Zigic and then King saw goal-bound efforts blocked.
But Derby should have doubled their advantage when Robinson raced through on goal only to fire emphatically over the crossbar with the goal at his mercy.
Clark sent on Hall for Chris Burke and the substitute quickly set about making an impression, leaving his marker for dead with an electric change of pace before firing a dangerous effort across the face of goal.
He then had Ledzgins scrambling across to his right with a looping strike from the edge of the area which bounced narrowly wide of the post.
Hall was finally rewarded for his efforts in the 73rd minute when he burst into the Derby box before being tripped by Rams skipper Richard Keogh. Referee Nigel Miller didn’t hesitate in pointing to the spot and King sent Legzdins the wrong way from the resultant penalty.
King almost grabbed a goal from open play moments later but his deflected drive from just inside the area bounced back off the crossbar.
Blues' top scorer was then heavily involved in the move which lead to Derby regaining the lead. As Blues cleared a corner King felt he was fouled as he attempted keep possession but the referee waved play on and, from the following ball back into the danger area, Sammon pounced on a knockdown with a left-footed finish which bobbled into the far corner.
But, not to be deterred, Blues responded immediately. Jonathan Spector found himself high up the pitch and whipped in a delicious cross for Lovenkrands to guide beyond Legzdins with his head and put Blues back on level terms once again.
The visitors pushed for a winner but Derby had the final say when Will Hughes found Jacobs on the left and he crossed for Tyson to poke home at the back post.