An estimated 100 million people in the US tuned in for the debate
Hillary Clinton and Donald Trump have clashed face-to-face on the debate stage for the first time in the race for the White House.
The Democratic and Republican candidates spent 90 minutes jousting in front of an estimated television audience of 100 million.
It was often bad-tempered and prickly as the pair clashed over familiar ground from what has become the most expensive election campaign in history.
It was also a remarkable insight into a relationship that once saw Mrs Clinton attend Mr Trump's wedding.
The pair began the debate by outlining their plans for the economy and creating jobs.
Hillary Clinton even broke the debate ice, telling Mr Trump: "Donald, it is good to be with you."
But she then criticised his tax plan - "Trumped-up Trickle-down" she called it - and highlighted the differences in their backgrounds, and how his plans would benefit the rich.
Mr Trump lambasted the political class, including Mrs Clinton, for allowing American jobs to leave the country.
The pair clashed over Mr Trump making money from the US mortgage crisis. "That's business," the billionaire said.
And he denied Hillary Clinton's accusation that he referred to climate change as a "hoax perpetrated by the Chinese".
The concept of global warming was created by and for the Chinese in order to make U.S. manufacturing non-competitive.— Donald J. Trump (@realDonaldTrump) November 6, 2012
In a bad-tempered exchange over trade, Mr Trump hit back: "You've been doing this for 30 years, why are you just thinking about these things now?"
She responded: "Donald, I know you live in your own reality."
Mr Trump even wheeled out one of his favourite phrases. "I'm going to cut taxes bigly."
The debate frequently descended into a shouting match. Donald Trump telling Hillary Clinton she had "been fighting ISIS all of her adult life".
Mrs Clinton said: "I feel I'm going to end up being blamed for everything tonight."
"Why not?" Mr Trump replied.
"A typical politician," he added. "All talk, no action."
"She has experience but it is bad experience"
Donald Trump again stonewalled when asked why he continues to refuse to release his tax returns. "What is he trying to hide?" Hillary Clinton asked.
He drew attention to Mrs Clinton's email scandal instead and dismissed her claims that it was a mistake.
She responded by laying into his business record: "I've met people who were stiffed by your businesses, Donald."
He claimed "tens of thousands of people are very happy, they love me".
On the issue of race and justice, which has again been thrust into the national headlines by police killings in Tulsa and Charlotte, they clashed again.
Mr Trump accused Mrs Clinton of not being tough enough: "We need law and order in our country."
He brought the issue of illegal immigration into the crime debate and called for a return of "stop and frisk" policing, which has been ruled unconstitutional.
Mr Trump was criticised for his indulgence of Vladimir Putin and was also forced to defend his questioning of Barack Obama's legitimacy as president - what Mrs Clinton called "a racist lie".
He repeated claims that ISIS had grown on Hillary Clinton's watch as Secretary of State. He again denied he had supported the war in Iraq.
Mrs Clinton called for fact-checkers to "turn up the volume" and respond to some of Donald Trump's claims.
In one of the night's more notable moments, Mr Trump claimed: "I have a much better temperament than she does.
"I agree she has experience but it is bad experience."
Mrs Clinton responded by listing Donald Trump's comments about women over the years.
"Vote as if your future depends on it because it does," she told the audience.
Opinion polls have shown that Donald Trump had closed the gap on Hillary Clinton in recent weeks, some even putting the candidates neck and neck with 42 days of the campaign to go.
They will face two more live television debates in the coming weeks, ahead of Election Day on 8 November.