On Wednesday, City failed to find a way past Manchester United. On Saturday afternoon it was the same story against a Birmingham outfit hovering above the drop zone but committed to blanket defending the hosts were unable to get past.
But disenchantment in the stands grew when Tevez was replaced by Gareth Barry in the final stages, forcing Mancini onto the back foot.
"I am frustrated as well," he said. "I wanted to win. I don't want to draw or lose.
"Carlos has had a little injury for two or three weeks and I felt if we took off that player we might have more chances to score.
"But if you think I put four strikers on and we score four goals, it is not true.
"All supporters are like this, in England and Italy. I must think like a manager. We can play wide, get the ball into the box, then we can score.
"Supporters just think why don't you put more strikers in the box, two, three, four, five."