United trailed at half-time to a Cameron Jerome goal despite dominating for large periods and needed a controversial own goal from Scott Dann to earn a share of the spoils. However, Ferguson was unhappy with referee Mark Clattenburg's decision to send off Darren Fletcher for a second bookable offence after a challenge on Jerome.
"To lose the goal just before half-time after dominating the game was a real sickener," he said. "But the most important thing is to persevere in situations like that. We have got the experience to do that."
He added: "But this is a tough league. Birmingham have really improved since they have come into this division."
Ferguson then turned his attention to Clattenburg, saying: "That referee did the Arsenal-Tottenham game earlier in the season and you needed to hit someone with an axe before he booked anyone in that game.
"There were some wonderful and weird decisions. The linesman gives offside for our goal - and it's an own goal!"
Blues boss Alex McLeish praised the way his side put a poor first half behind them to extend their unbeaten league run to a club record 12 games.
He said: "The dressing room was very noisy at half-time because the players knew they had not reached the standards of previous games.
"But we got a great response. We were fortunate to be leading at half-time but we were a different animal in the second half."
Source: PA
Source: PA