...that no one is talking about because there were so many other moments to talk about.
It came a few seconds before the 20:00 minute mark; the question was about gas prices. They had both answered and the President was responding to Mitt's (fairly effective) attack that gas prices had been under $2 four years ago but were over $4 now.
The President had already take Romney down on the issues of oil (that -14% number Mitt used BTW was for one year, the four year number is +10%) and coal (although I wish he had mentioned the coal workers who had to take time off without pay to be Mitt's political backdrop.
On gas prices, the President agreed they had been lower but as a result of going through the biggest recession since the Great Depression. He then conceded that Mitt might well be able to return us to those lower gas prices "because with his policies, we might be back in that same mess." -- and the audience made a noise for the first time. Looking at faces of the people sitting behind the President it was clear that line really hit home. Some laughed uncomfortably, the girl in the front row sighed and rolled her eyes as if to say "no kidding".
I think this was the moment that President Obama knew he was doing alright and he settled down a little and just laid into Mitt for the rest of the night.
PS: My second favorite moment of the night was then Mitt basically accused the Democrats of painting him as someone who doesn't care about 100% of the population. Yes, Democrats are saying that Mitt, but you said it first (and best).