ST Andrew's had been the scene of Owen Coyle's greatest triumph as Wanderers boss – but who knows what damage this Second City defeat has done to his grip on the manager's job?
Just as he and Wanderers appeared to have bought themselves some time with a weekend victory over Watford, Marlon King's second-half penalty plunged them straight back into panic mode heading for an equally daunting trip to Hillsborough in a few day's time.
Coyle had guided the Whites into the FA Cup semi-finals on this ground just over 18 months ago, and yet the packed stands of happy Boltonians on that day were replaced by a smaller, rather more sombre bunch who filed out into the cold night this time around.
Chris Eagles appeared to have repaired the early damage done by Leroy Lita, and make no mistake, this wasn't a performance as disappointing as that at Burnley nor Hull.
But damaging it most certainly was. And coupled with Jay Spearing's calf injury that forced him off the pitch in the first half, it all amounted to another woeful 90 minutes for the embattled boss.
Coyle chose to make only one change from the side that beat Watford at the weekend, bringing back Chung-Yong Lee on the right side of the midfield and dropping Keith Andrews to the bench, presumably with the Achilles problem that has troubled him since the start of the season.
The Irishman would enter the game sooner than expected – but not before Wanderers again made a bright start, only to fall behind to another goal with its origins out wide.
They even had the ball in the net 12 minutes in when Eagles picked out Ngog with a lovely reverse ball, only for the Frenchman's strike to be ruled out by the referee's assistant.
And their good work fell apart five minutes later when the lively Chris Burke combined well with Paul Caddis down the right, and the full-back slid a perfect ball into the six yard box for former Wanderers target Leroy Lita to smash home for his first Blues goal.
Mark Davies – looking in the mood early on - came close to levelling the scores when he picked up a flick from Kevin Davies on the edge of the box, only for his low drive to flick off the studs of Jonathan Spector and wide of goal.
Almost immediately, though, another quick break laid the Whites open bare and Wade Elliott's slide rule pass put Burke scampering in on Adam Bogdan's goal. Thankfully, the Hungarian stopped spread himself enough to block his shot and Mills was then able to pump the ball clear.
A two-goal deficit would have been harsh on the Whites, who in truth had mustered the better football in the first half. But it seemed as if they had spurned their best chance of going into the break on level terms when Ngog conspired to miss a free header from eight yards out.
Mark Davies found Eagles in space on the left, and the winger was able to swing a fine cross in towards the former Liverpool man, who despite being unmarked and having the whole goal to aim at, was only able to head tamely into the hands of Jack Butland.
It would have been the perfect riposte to the Birmingham fans who had been giving him a hard time for an incident that dated back to his Anfield days in 2009, when he 'won' a penalty from Lee Carsley before netting the winner.
But the home fans – sparse in number – were soon silenced when Steven Caldwell tripped Ngog around 30 yards from goal and Eagles curled a wonderful free-kick round the wall to beat sprawling keeper Butland to his left.
The appearance of guest of honour Fabrice Muamba on the pitch at half time served to warm up both sets of fans – but once again, the Whites came out stone cold.
Within two minutes, Birmingham had gone 2-1 up as linesman Steven Copeland spotted a foul on Marlon King off the ball as David Murphy swung a cross in.
King picked himself up to send Bogdan the wrong way from the spot, and Wanderers were right back where they started from.
It could have quickly got worse. Bogdan beat away an angled drive by Burke and Lita drilled a shot into the side netting after getting around the keeper.
That prompted Coyle into a last throw of the dice. Martin Petrov and Benik Afobe were thrown on after an hour, with Ngog and Chung-Yong withdrawn.
And Afobe nearly had the desired effect after just two minutes, with Butland making an important stop at the on-loan striker's feet.
Petrov then followed suit 10 minutes later, volleying just over the top after a floated pass from Kevin Davies.
Try as they may, Wanderers couldn't get themselves back into it. And worse still, they always looked susceptible on the break, with sub Nathan Redmond forcing Bogdan into one fine save late on.
Alonso also brought a world class save out of Butland with a stinging drive. But this time, unlike April 2011, there was no fairytale ending.
Birmingham (4-4-2): Butland, Spector, Mullins (Fahey 46), Caldwell, Murphy, Burke, Ibanez, Elliott, Caddis (Davies 54), King, Lita. Not used: Doyle, Morrison, Lovenkrands, Redmond, Asante Wanderers (4-4-2): Bogdan 6; Mears 5, Mills 6, Knight 6, Alonso 5; Chung-Yong 5 (Petrov 6, 61), M Davies 7, Spearing 6 (Andrews 5, 17), Eagles 7; K Davies 6, Ngog 6 (Afobe 5, 61). Not used: Lonergan, Ricketts, Sordell, Pratley Attendance: 14,693 Referee: Carl Boyeson (East Yorks)