Birmingham moved back into second place in the Championship on Saturday despite only claiming a goalless draw away to rock-bottom Charlton.
Blues were leapfrogged by Sheffield United on Friday night, and although they reclaimed an automatic promotion spot they are now four points behind leaders Wolves - whom they beat 2-0 earlier this week.
Worryingly for the visitors, there was little to distinguish between the side pushing for promotion to the top flight and the team all but doomed to League One. The Addicks could be relegated on Monday if they lose at Coventry.
And it was Charlton who should have taken all three points at The Valley but Zheng Zhi fluffed a glorious chance to win the game late on.
The fact that the best player on display was a 17-year-old, Charlton's exciting rookie Jonjo Shelvey, summed up a disappointing game.