Mark Pembridge emerged as Fulham's goalscoring hero with a fine second half goal which enabled the London club to make progress into the fourth round of the Carling Cup.
The tenacious Welsh international took full advantage of Birmingham's inability to dominate the game when he scored a spectacular winner in the 77th minute with a tremendous wind assisted drive.
It was another frustrating game for Birmingham who are definitely missing the considerable influence of their striker, Mikael Forssell.
Fulham, however, battled bravely despite being under heavy pressure for long periods.
Birmingham paid for their lack of goalscoring with Dwight Yorke and Emile Heskey struggling to live up to their big-name reputations.
The absence of Robbie Savage, who was surprisingly rested by manager Steve Bruce, was also a key factor in Birmingham's failure to progress.
Weak finishing has been Birmingham's problem and it was again in the early stages when Yorke was guilty of missing three reasonable chances.
Yorke's worst miss occurred in the 17th minute when the former Manchester United striker made contact with a Jamie Clapham cross but shot straight at goalkeeper Mark Crossley.
Fulham, beaten in their last three matches, were far from impressive on their second visit to the Midlands in the space of five days.
They struggled to get into gear and on a very slippery surface struggled to make any impact. Skipper Andy Cole, a colleague of Yorke at both Manchester United and Blackburn, was generally well held by Kenny Cunningham.
When Cole made his first break he was quickly tackled out of possession by Mario Melchiot.
Crossley, meanwhile, continued to distinguish himself as he demonstrated with a brilliant diving save from a Jesper Gronkjaer cross-shot.
In a strong wind, Birmingham had the upper hand but they contrived to waste good opportunities with Clapham driving just wide.
Maik Taylor, formerly of Fulham, was a lonely spectator a long period, but he was alive to the situation when he had to make a late desperate save to keep out a Claus Jensen shot which took a late deflection.
When these two teams have met in recent times there have been fireworks but it was not the case on this occasion as they both struggled to hit the high notes.
It was often very frustrating with few highlights although Darren Anderton enjoyed a good game in place of the rested Savage.
Birmingham had a scare in the 65th minute when Matthew Upson twice failed to make contact and allowed Cole to break down the right before providing a low cross for Jensen only to see Taylor block a close-range effort.
It was a warning that Birmingham failed to heed as in the 77th minute the Londoners took a shock lead very much against the run of play when the unmarked Pembridge rammed home a terrific cross-shot from just outside the penalty area.