Hillary Clinton Hillary Diane Rodham ClintonButtigieg stands in as Pence for Harris's debate practice Senate GOP sees early Supreme Court vote as political booster shot Poll: 51 percent of voters want to abolish the electoral college MORE allies are feeling even more confident in her chances after what they characterized as her dominant performance in the final 2016 presidential debate on Wednesday night.

A well-prepared Clinton commanded the stage for the 90-minute bout in Las Vegas, her supporters said, chipping away at Republican nominee Donald Trump Donald John TrumpOmar fires back at Trump over rally remarks: 'This is my country' Pelosi: Trump hurrying to fill SCOTUS seat so he can repeal ObamaCare Trump mocks Biden appearance, mask use ahead of first debate MORE’s policies, his temperament and even his demeanor toward women.

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“He and his staff might not know this, but he is done,” said Jim Manley, the Clinton surrogate and Democratic strategist. “He had one last chance to expand his base tonight [more] than he did in the last two debates, but he is dead man walking.”

While Clinton supporters gave Trump credit for appearing more poised and disciplined — particularly during the first 30 minutes — they argue he didn’t do himself any favors as the debate carried on.

“As usual, he dissembled after 30 minutes,” one former Clinton aide concluded.

And that was before Trump refused to say he would accept the election’s results, a moment that quickly became the dominant news from the debate.

“Wheels off the wagon,” the former aide said. “Trump’s unsuitability was clear.”

Clinton called the moment “horrifying” and followed up by labeling Trump as a sore loser who couldn’t even be graceful when his show "The Apprentice" didn’t win an Emmy.

“Should have gotten it,” Trump said in a moment cable networks played back repeatedly.

One longtime adviser called the remark “devastating” for Trump, saying he had squandered any chances he had of making a comeback in the race.

The Republican nominee has trailed Clinton in national polls and is either tied or losing in most swing states.

On CNN’s post-debate analysis, David Axelrod, a former strategist for President Obama, called the evening a “disaster" for Trump. And later he concluded that, “No one in modern history has recovered from a deficit like this.”

Clinton "showed why she’s ready for he job,” the former aide said. “There couldn’t have been more of a contrast.”