WATCH: Why the Winner of the Democratic Debate Was ... Anderson Cooper 

Although there's some debate about who was the clear-cut winner of Tuesday's Democratic presidential debate, there is a consensus among many media critics as to the real star of the night: moderator Anderson Cooper.

The out CNN anchor and broadcast journalist of more than 20 years was praised by critics for his work asking questions of the five most prominent Democrats running for president, including the two leading the polls, former Secretary of State Hillary Clinton and Sen. Bernie Sanders of Vermont.

"Cooper hammered each candidate with questions about their biggest weak spots," wrote The Huffington Post's Alana Horowitz Satlin of Cooper's ability to hold each candidate accountable. "He asked former Secretary of State Hillary Clinton and former Rhode Island Sen. Lincoln Chafee about their wavering political stances. He grilled Vermont Sen. Bernie Sanders and Virginia Sen. Jim Webb for their high marks with the NRA. He questioned former Maryland Gov. Martin O'Malley's record as mayor of Baltimore, a city plagued by recent unrest. And he asked all of the candidates about their electability, putting the three Democrats who are polling in the single digits in a tough spot."

"Cooper moderated the panel like a journalist who actually cared about the debate; throughout the night, he consulted copious notes, quoted statistics, and pressed for clearer answers, doing exactly what the fourth estate ought to. He was neither ingratiating with the candidates nor patronizing with the viewers," said Salon television critic Sonia Saraiya. "There were hiccups -- a question about pacifism directed at Sanders didn't quite make sense, and a post-bathroom-break joke appeared to be taking a jab at Clinton for being female. But given that Cooper had to manage two outspoken frontrunners, three no-name cold fish, several hot button issues, and commercial breaks, these are small hiccups, indeed."

The highest praise for Cooper was that he presented himself as a consummate professional, ready with questions that actually mattered.

"In the end, Cooper showed why he's one of the top journalists in the game: He was impeccably prepared, wasn't hesitant to ask follow-up questions when warranted and didn't offer up one question -- not one -- that could be considered frivolous or fluffy. ... A solid A," said Joe Concha of Mediaite.

Watch Cooper's work as moderator in CNN's video of the full Democratic presidential debate, below.