A goal-drought at St Andrew's is broken, a contentious penalty will occupy all the post-match reaction and all three points go into Birmingham City's Christmas stocking.
Defensively, Blues were enormous as they protected their lead against a Cardiff side that will feel aggrieved.
Read Ged Scott's full report here.
That's all we've got time for tonight.
Enjoy the rest of your evening, but be sure to return to the BBC Sport website on Saturday for live text commentary of the top-of-the-table clash between Brighton and Middlesbrough (kick-off 12:30 GMT).