Washington: Hillary Clinton has pulled ahead of presidential rival Donald Trump in a new national poll out Friday, just days after her strong showing in the first televised debate.

The Democrat and former secretary of state bested her Republican rival by three percentage points in a Fox News poll which showed her ahead 43 to 40 per cent.

Although Clinton’s lead is within the poll’s three percentage point margin of error, it shows a bump for Clinton, who beat Trump by only one percentage point in the same poll two weeks ago.

Libertarian candidate Gary Johnson and Green Party candidate Jill Stein polled at eight and four per cent respectively.

The nationwide results come as Clinton’s numbers improve in a number of critical swing states following the debate.

Florida — with its prodigious number of electoral votes — has swung back toward Clinton since Monday’s political showdown, polling shows, offering her a tantalising opening to reach the White House.

Meanwhile a Detroit News-WDIV-TV four-way matchup conducted in the battleground state of Michigan found Clinton leading Trump by seven percentage points after the debate.

The first of three, the debate was the most watched in US history with 84 million people tuning in, according to a Nielsen tally.

During the clash the Democrat frequently forced her prickly opponent on the back foot over judgment, taxes, foreign policy and terrorism.

But American voters do not particularly like either candidate and many are still undecided.

The Fox News poll found that 53 per cent had an unfavourable opinion of Clinton, while 55 per cent view Trump in a negative light.

The number of voters who find Trump honest and trustworthy, meanwhile, sank eight points since mid-September to 31 per cent.

Clinton’s numbers remain relatively unchanged: 35 per cent now find her honest and trustworthy compared to 34 per cent two weeks ago.

The Fox News poll interviewed 1,009 registered voters, and includes results among 911 likely voters. It was carried out Tuesday through Thursday.