President Barack Obama and Republican challenger Mitt Romney clashed over taxes, deficits and how to revive the US economy as they shared the stage for the first time in a high-stakes debate with the power to reshape the race for the White House.
Mr Obama said Mr Romney wanted to return to the policies that hurt the US economy. Mr Romney said Mr Obama's policies had failed and America needs a change.
"Going forward with the status quo is not going to cut it for the American people who are struggling today," Mr Romney said.
The showdown was critical for Mr Romney, a former Massachusetts governor. With five weeks to go before the election, polls show Mr Obama leading in the most important states in what is a state-by-state vote that decides the presidency. Still, the race remains tight and the three debates this month give Mr Romney an opportunity to shift the momentum, taking on Obama before a television audience of tens of millions.
Mr Romney was particularly aggressive, like a man looking to shake up the campaign with a little less than five weeks to run. He said that under Mr Obama's policies "middle-income families are being crushed".
Mr Obama has argued that he prevented a meltdown after inheriting an economy in free fall from the Republican administration of George W Bush. Mr Obama accused Mr Romney of wanting to "double down on the top-down policies" that led to the economic crash four years ago.
After Mr Romney said he would repeal and replace regulations passed after the 2008 financial crisis, Mr Obama responded: "Does anyone think there is too much oversight and regulation of Wall Street?" If so, "Governor Romney is your candidate."
Mr Obama said his opponent's plan to reduce all tax rates by 20% would cost 5 trillion US dollars (£3 trillion) and benefit the wealthy at the expense of middle income taxpayers. Mr Romney shot back: "Virtually everything he just said about my tax plan is inaccurate."
Many commentators and viewers were sure to focus on the style and body language of the two candidates. Mr Romney often comes across as stiff and distant, while Mr Obama is seen as warmer and more empathetic with everyday Americans. Polls show that most people expect Mr Obama to outperform him at the debate.
The next two debates are on October 16 in New York and on October 22 in Florida. Vice President Joe Biden and Mr Romney's running mate, congressman Paul Ryan, have one debate, on October 11 in Kentucky.