Blues fell to a desperately disappointing home defeat to Burton Albion at St. Andrew’s.
Lloyd Dyer netted against his former loan club for the second time this season to open the scoring in the first-half and Lucas Akins added a second goal early in the second period.
It could have been a very different game if Blues hadn’t passed up a golden opportunity to take the lead inside the opening four minutes.
A poor punch clear from Burton goalkeeper Jon McLaughlin, who had advanced to the edge of his area, saw the ball land at the feet of Lukas Jutkiewicz. But, with an open goal gaping, Blues’ top scorer sent his half-volley wide of the left post.
At the other end, Dyer was presented with a very good early chance when he was sent clear on the left side of the Blues area. Ryan Shotton tracked back and slid in well to block, although Dyer’s effort was flying wide anyway.
Robert Tesche, Krystian Bielik and Che Adams all tried their luck with shots from outside the area as Blues searched for a morale-boosting opening goal.
The visitors were forced into a change of goalkeeper on 29 minutes as McLaughlin failed to shrug off an injury caused when Adams fell on him during a challenge for the ball. Stephen Bywater came on to take his place between the posts.
Burton took the lead on 36 minutes. Tomasz Kuszczak spilled a shot from Akins and, after a scramble inside the six-yard box, Dyer was on hand to stroke the ball into the net.
Tesche’s out-swinging cross was veering towards Jutkiewicz at the far post as Blues looked to respond but Burton captain John Brayford stretched out a leg to make a crucial intervention.
Adams then took the initiative when he found himself a bit of space 30 yards out and unleashed a fierce low drive that flashed narrowly wide of the target. It was a rare highlight of a nervy and uninspiring first-half.
Blues made two changes at the break with Gardner and Kuszczak (who went off due to a shoulder injury) replaced by Kerim Frei and Adam Legzdins, the former Burton keeper receiving a good ovation from the travelling fans.
But it was the Brewers that made the more positive start to the second period, Luke Varney with an acrobatic overhead-kick that went just over the bar. Blues didn’t heed the warning and, on 52 minutes, Nigel Clough’s side doubled their advantage, Akins turning the ball home from close range after the hosts failed to clear a corner.
That was the catalyst for the third and final Blues substitution as Jacques Maghoma replaced Emilio Nsue.
Blues continued to struggle to create any clear openings and instead it was Burton that came within a whisker of adding a third. A slip from Bielik allowed Varney a run on goal, Maghoma raced back and slid in with a vital intervention.
However, Maghoma's tackle sent the ball flying past Legzdins and fortunately the post came to Blues’ rescue.
Moments later Jackson Irvine should have done better when he was teed up only 10 yards out but the Brewers’ top marksman lent back and fired his shot well over.
Frei’s 25-yard free-kick curled a fraction over the bar as Blues looked for a way back into the game.
With eight minutes left, Bielik’s long-distance shot was deflected into the path of Adams who crashed a low effort into the side-netting.
In the final minute of normal time, the hard-working striker latched onto another ball played over the top of the Burton defence and, from a narrow angle, fired in a shot that was parried away by Bywater.
The lively Adams created Blues’ final chance when his cross was met by a Jutkiewicz header that was easily claimed by the Burton keeper.
This result saw Blues drop to 20th, three points above the Sky Bet Championship relegation zone, and led to the resignation of manager Gianfranco Zola an hour after the game.