According to the poll, the result was similar to Mitt Romney's dominant performance over President Barack Obama in the first 2012 presidential debate.
Voters who watched said Clinton expressed her views more clearly than Trump and had a better understanding of the issues by a margin of more than 2-to-1.
Clinton also was seen as having done a better job addressing concerns voters might have about her potential presidency by a 57 per cent to 35 per cent margin, and as the stronger leader by a 56 per cent to 39 per cent margin.
The gap was smaller on which candidate appeared more sincere and authentic, though still broke in Clinton's favour, with 53 per cent saying she was more sincere to 40 per cent who felt Trump did better on that score. Trump topped Clinton 56 per cent to 33 percent as the debater who spent more time attacking their opponent, the poll showed.
Although the survey suggested debate watchers were more apt to describe themselves as Democrats than the overall pool of voters, even independents who watched deemed Clinton the winner, 54 per cent to 33 per cent who thought Trump did the best job in the debate.
About half in the poll said the debate did not have an effect on their voting plans, 47 per cent said it did not make a difference, but those who said they were moved by it tilted in Clinton's direction, 34 per cent said the debate made them more apt to vote for Clinton, 18 per cent more likely to back Trump.
On the issues, the voters said Clinton would do a better job handling foreign policy, 62 per cent to 35 per cent, and most thought she would be the better candidate to handle terrorism, 54 per cent to 43 per cent who preferred Trump.
But on the economy, the split was much closer, with 51 per cent saying they favoured Clinton's approach to 47 per cent who preferred Trump.
Overall, 55 per cent of the voters said they did not think Trump would be able to handle the job of president, 43 per cent said they thought he would.
Asessments of Trump's attacks on Clinton were sharply split by gender, with 58 per cent of men seeing them as fair compared with 44 per cent of women who watched the debate.
The CNN/ORC post-debate poll includes interviews with 521 registered voters who watched the Monday night's debate. Results among debate-watchers have a margin of sampling error of plus or minus 4.5 percentage points.
Respondents were originally interviewed as part of a September 23-25 telephone survey of a random sample of Americans, and indicated they planned to watch the debate and would be willing to be re-interviewed when it was over.
First Published: 27 Sep 2016 07:28 AM