Hart was in inspired form as he produced a string of impressive saves to earn City a draw against the German club and admits that it was unusual to be so busy in goal.
"Normally I don't feel I do a great deal in a Man City shirt, so when required I like to step up," said the 25-year-old. "But it was like being down at the park getting peppered by your mates.
"We are in with the big boys now and there is no place to hide.
"There is no point being on a learning curve if you are not going to win."
City are currently third in Group D after two games.