Garry Monk insisted he would treat this victory like any other but it was a win which carried far greater significance than simply the three points to accompany it.
Birmingham brought Leeds United's unbeaten record, the last in the Championship, to a halt with a result which few outside the confines of St Andrew's would have felt conceivable from a side without a win since May. This crazy outcome perfectly summed up the topsy-turvy nature of the division.
Monk, the former Leeds manager who left in acrimonious circumstances 16 months ago after less than a year in charge, was mercilessly baited by home fans in a 34,800 crowd, but the 39-year-old's players provided the perfect riposte.
'It wasn't about me,' he insisted. 'This result has been coming. There's been a lot of talk about our winless run but if you've watched our performances this season you'd know we deserved this, it has been coming.'
Birmingham got their noses in front thanks to two preventable goals from their forward Che Adams, then hung on grimly.
It was a wonderfully backs-to-the-wall rearguard from the Blues, who took an eighth-minute lead when Adams' speculative effort from 18 yards caught goalkeeper Bailey Peacock-Farrell flat-footed to find the bottom corner.
There were similarities with the second just before the half-hour, when Adams was allowed to turn after taking a pass from Lukas Jutkiewicz to beat the Leeds keeper with a low drive which found the net via the post.
Then it was heavy Leeds pressure as the leaders looked for a way back, only to be thwarted by some uncharacteristically poor passing, wasteful finishing and heroic defending, in addition to no little time-wasting from Monk's men.
Harlee Dean blocked brilliantly to deny Tyler Roberts, before Ezgjan Alioski set up a tense finale which included eight minutes' injury-time with a confident close-range finish.
The hosts almost leveled at the death only for Lee Camp to produce a stunning save to keep out a low 18-yard Stuart Dallas effort.
Midfielder Kalvin Phillips was taken off in a first-half reshuffle but the damage had already been done. Manager Marcelo Bielsa said: 'The team I chose for beginning of this game wasn't right.
'We had to right what was wrong because I made a mistake. We weren't fluid for the first 30 minutes and we looked tired.'