(CNN) The majority of the frontrunners for the 2020 Democratic presidential nomination crowded onto 10-person debate stage in Miami Thursday night , the second half of a debate-a-thon that began 24 hours earlier with 10 more aspirants duking it out for precious media attention and that most valuable and elusive commodity in national elections: Buzz.

Unlike the relatively polite affair on Wednesday night, the candidates in Thursday's debate came out ready to scrap. It was a much more spirited affair and produced a series of powerful moments -- the vast majority authored by California Sen. Kamala Harris

I watched all two hours, tweeted and took some notes. My thoughts on the best -- and the worst -- of the night that was is below. (For my winners and losers of night one, click here .)

WINNERS

: The California Senator gave the strongest performance not just of Thursday night's debate but of either nights' debate. She was calm, poised, knowledgeable and, yes, presidential. She had the biggest moment of the night when she cut through a series of shouting voices to insist that the American public wanted to hear how the candidates were going to put food on their table, not witness a food fight. She clearly had that line ready going into the debate but that doesn't change the fact that she delivered it at the perfect time and without missing a beat. Her deeply personal recollection of her own experiences with race in California -- and her scolding of Joe Biden for his support of anti-busing legislation was hugely powerful. One potential problem for Harris going forward: She came out Thursday night for totally abolishing the private insurance industry, which seems to run counter to what she told CNN's Jake Tapper last month

* Pete Buttigieg: If you knew nothing about Buttigieg going into Thursday night, you would have assumed from his performance that a) he was a senator or a governor who had been at this for a long time and b) a co-frontrunner with Harris in the race. That person would be stunned to learn that Buttigieg is currently the mayor of South Bend, Indiana, and running at the back of the lead pack. He was serious, smart, thoughtful and probing. His outspokenness on why Democrats need not cede religion to Republicans was powerful. His answer on the officer-involved shooting in his hometown was clearly well rehearsed, yes, but it was about as a good an answer as he could give on such a difficult issue. Buttigieg has lots and lots of natural political ability -- and it shone through on Thursday night.

* Michael Bennet: Look, I don't think that the Colorado senator is somehow going to shoot from 1% to relevance in the polls based on his performance in this debate. He wasn't that good. But, for someone who a) no one knew going into this debate and b) had limited speaking opportunities to make his case, I thought Bennet performed well. Bennet's incredulity with Biden's belief that Senate Majority Leader Mitch McConnell would start working in a bipartisan way if the former vice president won the White House felt genuine -- and was powerful. In short: Bennet came out of this debate looking better than he went into it. Which is a win.

LOSERS

*Joe Biden: Well, that went poorly. From the get-go, Biden seemed too rigidly attached to his stump speech and his talking points. He struggled to fit his points into the 60-second time limit. He got defensive -- as we predicted -- when Harris pushed him on his comments about segregationist Sen. James Eastland and his opposition to school busing and quite clearly lost the back and forth. Badly. (Checkmate @KamalaHarris. Sorry @JoeBiden! Put a [fork] in him," : Well, that went poorly. From the get-go, Biden seemed too rigidly attached to his stump speech and his talking points. He struggled to fit his points into the 60-second time limit. He got defensive -- as we predicted -- when Harris pushed him on his comments about segregationist Sen. James Eastland and his opposition to school busing and quite clearly lost the back and forth. Badly. (Checkmate @KamalaHarris. Sorry @JoeBiden! Put a [fork] in him," tweeted Donald Trump's 2020 campaign manager Brad Parscale .) When Biden was asked what his first act as president would be, he said it would be to defeat Donald Trump. Uh...The only extended applause lines Biden received were when he mentioned Barack Obama. But Obama isn't on the ballot and isn't endorsing Biden. It was a very shaky start for Biden. Very.

* Bernie Sanders: The Vermont senator learned a tough lesson Thursday night: Debating nine people as one of the frontrunners for the nomination is a very different beast than debating a single, establishment frontrunner when you are the freewheeling insurgent. Rather than passionate, Sanders came off as just plain loud. Rather than committed, he came across as repetitive. And, even worse, there were large periods of the debate where Sanders seemed to just plain disappear. Sanders' worst -- and most damning -- moment? Moderator Rachel Maddow read him a quote of his about guns. Sanders responded: "That's a mischaracterization." Maddow retorted: "It's a quote of yours." The audience laughed -- at Sanders. Oomph.

* Marianne Williamson: Watching the author and spiritual adviser on the debate stage reminded me of my own experience playing high school basketball: Hopelessly out of her league. It's not that Williamson isn't a politician, it's that she had zero idea how to navigate a crowded debate stage and make her points. It was also problematic that she didn't seem to have any, you know, points.

* Andrew Yang: Yang's online army insisted that this first debate would be his break-out moment -- a chance to push his message of the dangers of automation to the general public. The only thing that evoked automation was Yang; in the few moments when he spoke, he sounded like a robot.

* Eric Swalwell: You know that guy in high school who has a catchphrase? And, the first time you hear it, you're like "That's not bad!" But by the time he says it for the 30th time before lunch, you have to fight down the urge to vomit in your mouth? That's Eric Swalwell and "pass the torch."

This piece has been updated.