The Englishman's brilliance had kept the hosts in the game as the German champions attacked with intent and Neven Subotic's handball in the area prompted the spot kick that provided Roberto Mancini's men with their first point of the group stage.
Balotelli kept his cool, despite Roman Weidenfeller's attempts to distract him before the effort from 12 yards, but the City No.1 had no doubts that the Italian would score.
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"I hope the effort we've made in both Champions League games hasn't been wasted, we're focused on qualifying from this group. But, as you can see, for the [lowest-seeded] team, it shows what a group we're in.
"We've got to be happy with the point. I think it could have been 10-10, I thought their keeper was fantastic and they had a lot of chances.
"You know Mario is never going to miss that penalty.
"I don’t know, I've not seen it if it was a penalty, but I think we pushed hard and we wanted the point in the end. We can't deny that.
"We needed a point from the game. It would have been nice to win but we've come out alive and the group's still alive for us."
Asked if he had ever before needed to make so many saves in one match, Hart mused: "Not off the top of my head.
"Unfortunately I didn't stop all of them, I would have liked to but Dortmund were different class tonight and it took a good defensive effort to keep it to one."
A second-half substitution briefly changed City to a three-at-the-back system, during which time Marco Reus seized upon a Jack Rodwell error to score, but the goalkeeper does not feel that the formation was to blame.
"They were getting chances whether it was four at the back or 10 at the back or one at the back," he insisted. "I think they were always going to get chances.
"Unfortunately the pass was a bit short and he took the goal well. And we've moved on and Mario was called on and took his goal well."