Birmingham boss Alex McLeish said: "I was really pleased for Garry O'Connor.
"He has now played in three successive games and he is obviously playing better from playing regularly in the side.
"He produced a fine all-round performance and, with a bit of luck, could have had a hat-trick."
Palace boss Neil Warnock had every reason to be disappointed with the result.
He said: "We have now played Wolves, Birmingham City and Reading away from home already this season and we should have won all three games.
"I am pleased with the way we have bounced back since the early games and it took a freak goal in the fourth minute of injury time which cost us the game.
"If Kevin Phillips hadn't shanked his shot we would not have conceded the O'Connor goal.
"But the lad deserved his goal for his first-half performance when he twice went close to scoring."