Body language expert: Hillary owned the debate from the moment she walked on stage

Clinton also got to show another side to her personality.

A highlight of the debate was when Sanders proclaimed, "Enough of the emails!" in reference to this year's scandal surrounding the private server Clinton used as Secretary of State. Morgan said that Clinton had the perfect response, laughing genuinely and then shaking his hand in gratitude.

"It was a win-win for the both of them," Morgan said. "He got his funny line in and ... that was a nice moment for her, a very human, warm, connected kind of moment."

Morgan said that Clinton faltered, however, when she tried to allude to this amusing moment later, when Lincoln Chafee brought the email issue back up and CNN moderator Anderson Cooper asked Clinton if she wanted to respond. She simply replied, "No," which got a big reaction, and smiled wide as she said it.

Despite the cheering of those already in her camp, Morgan said the moment served as a reminder that the email controversy dragged on so long because she initially refused to respond seriously to allegations of wrongdoing, and made her seem disingenuous.

"Had she said 'no' with a serious expression on her face, she probably could have put that to bed then and there," Morgan said.

As for the body language of the other candidates, Morgan said:

Lincoln Chaffee: "I mean, I think if he isn't finished as a result of that evening then it won't be long. But he certainly didn't look presidential."

Jim Webb: "We all expect our debaters to be a little stiff and nervous at first, perhaps, but expect them to be comfortable by the end. But he never really eased into it, except to complain that he wasn't getting enough air time. So he didn't do himself any favors."

Martin O'Malley: He has great stage presence, but didn't have to content to back it up, Morgan explained. "He's the tallest person on the stage, he's very good-looking, he's got good posture, and so just showing up and being seen on the same stage with Hillary and with Sanders is a win for him ... It took him a long time to get over the nervousness, so he didn't put in a strong performance."

Bernie Sanders: "I think the only problem with Bernie is he's a ranter, and do we really want a ranter to be our president? It's like Donald Trump. We respond to the emotion and we respond to the apparent authenticity, but in the long run will people want that?"

And as for competition in the GOP, Morgan said Clinton's performance stacks up well.

As one of two female candidates in the race, Morgan said Clinton has the advantage because she's never had to prove that she can fit the archetype of "strong woman" — no one's questioned her strength.

Morgan said he'd be interested in seeing Clinton go up against Donald Trump, because "Anytime you put Trump in a room with people, he's going to dominate." Trump knows how to keep the cameras and audience focused on him even when he's not speaking, through animated expressions. Morgan said that if he were coaching Clinton to debate Trump, he'd say to treat him "like an unruly child," and to express moments of exasperation at some of his more bombastic statements.

Going forward in the race, Morgan said, "Hillary is certainly going to present a strong, authoritative, fully-capable-of-being-an-executive persona. She's going to come out with that kind of reserved strength."

But in this campaign cycle, where Americans seem "to be craving authentic outsiders," Clinton is going "to have to dial up her game a little bit and continue to find places where she can show some emotion in a way that is consistent," Morgan said. "And that's tough, because that's not been her game. Her game has been to be reserved and protect herself and play it close."