One memorable line by Hillary Clinton sums up Monday's debate

Hillary Clinton nailed Donald Trump during Monday's presidential debate with a line that many believe sealed an exceptionally strong night for the former Secretary of State.

After a heated moment in which Trump criticized Clinton for taking time off the campaign trail to prepare for the debate, Clinton responded pithily that the debate wasn't the only thing she prepared for.

"I prepared to be president, and I think that's a good thing," Clinton said.

The audience signaled its approval by cheering for Clinton - thereby breaking debate moderator Lester Holt's rule against audience applause. Trump responded by rolling his eyes.

This moment was hailed by many as a turning point in the debate.

For the first half hour, Trump demonstrated an ability to stay on message and highlight his campaign pillars. The "preparedness" exchange that followed was indicative of the following hour - Clinton maintained a steady grasp on policy specifics and her campaign message and baited Trump into interrupting her and Lester Holt with heated rhetoric and quibbling over things he had said or not said in the past.

The exchange came after Trump went on a lengthy tangent about how "badly" he believed politicians had failed inner city youth.

"And I will tell you, you look at the inner cities -- and I just left Detroit, and I just left Philadelphia, and I just -- you know, you've seen me, I've been all over the place," Trump said. 

He continued: "You decided to stay home, and that's OK. But I will tell you, I've been all over. And I've met some of the greatest people I'll ever meet within these communities. And they are very, very upset with what their politicians have told them and what their politicians have done."

Clinton stayed silent throughout Trump's diatribe, but then cut in when Holt tried to interject.

"I think Donald just criticized me for preparing for this debate. And yes, I did," Clinton began. "And you know what else I prepared for? I prepared to be president, and I think that's a good thing."

Here's the moment: