A first-half wonder strike by Brandon Khela handed 10-man Birmingham a narrow 1-0 Carabao Cup win at League One rivals Charlton.
Both teams making many changes – the hosts making five, while the visitors made eight – did not prevent a lively opening to the tie.
Charlton should have taken the lead after just 12 minutes, when Tyreece Campbell was upended in the area by Tyler Roberts, however, the 20-year old fired directly at goalkeeper Ryan Allsop, who collected the ball comfortably.
Luke Harris almost gifted Luke Berry a goal after 26 minutes with a loose pass, but the Charlton midfielder drove his effort just wide of the post.
Birmingham stunned the hosts after 32 minutes with a beautiful curled effort from over 20 yards out by Khela as he celebrated his first goal for the club.
The Blues looked more likely to add the second goal of the night and Alfie May should have done better as he sent a weak 65-minute shot at Will Mannion after finding space.
Charlton were badly missing the spark needed to draw level in the contest, although they were handed a boost after 77 minutes when Dion Sanderson saw red for his second caution.
After a Greg Docherty shot was fired across goal in stoppage-time, Birmingham saw the contest out to progress to the second round.
