Clinton reportedly defeats Trump in the first US Presidential debate

Hillary Clinton has emerged as the winner in the epic first US presidential debate, as Donald Trump tied himself in knots and let his frustrations boil over as the contest dragged on.

Trump began the debate strongly, excelling as he argued on his own terms about the perils of "badly negotiated" free trade deals killing blue collar jobs, his business-tax-slashing plan to create jobs and the failed establishment political class that Clinton personifies.

Yet the showman failed to sustain the momentum. Clinton and the debate moderator got under his skin on his failure to release personal tax returns, public records showing he did in fact support the Iraq war despite repeatedly denying it and his spreading of false rumours about Barack Obama's nationality.

In a successful blow, Clinton created doubts about whether Trump paid any federal tax and laid bare his alleged discrimination against African Americans at his company's rental apartments in the 1970s.

A frazzled Trump took Clinton's bait on almost every occasion and wasted valuable time giving confusing counter punches to accusations hurled at him as he lost control of the debate agenda.

"Trump was Trump and it wasn't a good night for him," said David Axelrod, a former campaign strategist for Barack Obama.

In contrast, Clinton was well prepared, on message, and disciplined at painting Trump as a shonky businessman who wants to cut taxes for the rich. A poised Clinton talked up the benefits of alliance-based foreign policy and reminded voters of her government experience to handle uncertain national security dangers.