(CNN) -- The highly anticipated debut debate between Hillary Clinton and Donald Trump lived up to its billing Monday as the candidates clashed repeatedly over the economy, tax cuts for the wealthy and ISIS.
As Trump slammed Clinton for staying off the campaign trail recently as he traveled the country, Clinton responded with her best zinger of the night.
"I think Donald just criticized me for preparing for this debate," she said. "And yes, I did. And you know what else I prepared for? I prepared to be President. And that is a good thing."
The line drew a round of applause from an audience that had been instructed to remain quiet.
Trump's tendency to make false claims was on full display during the debate as he made inaccurate statements on everything from laws regarding policing, his support for the Iraq War and his contention that Clinton was behind the so-called birther conspiracy.
Clinton, the Democratic nominee, repeatedly sought to correct Trump's statements -- going so far as referring viewers to fact checks on her website -- as she aimed to portray him as out of touch with the complexities of the American economy.
"I know you live in your own reality," she told Trump.
Powerful moment
One of the most powerful moments of the debate came when the conversation focused on the birther debate following Trump's recent acknowledgment that President Barack Obama was born in the US -- a fact that has been evident for years. With Trump standing just a few feet from her, Clinton blasted Trump for perpetuating a "racist lie."
"He has a long record of engaging in racist behavior," Clinton said as Trump shook his head.
Trump hit back noting Clinton's tough critiques of Obama during their bitter 2008 primary battle.
"You treated him with terrible disrespect and I watch the way you talk now about how lovely everything is, ... it doesn't work that way," he said. "When you try to act holier than thou, it really doesn't work."
Clinton and Trump opened the debate on a positive note by shaking hands before stationing themselves behind their podiums at Hofstra University on New York's Long Island. The debate is attracting worldwide interest with a television audience expected to approach 100 million, lured by the extraordinary drama of the 2016 campaign.
And that drama quickly unfolded.
An increasingly angry Trump slammed Clinton for putting her plans to fight ISIS on her website -- and thereby tipping off America's enemy.
"Well, at least I have a plan to fight ISIS," Clinton responded, referring to his previous statements that he has a "secret" plan to destroy the terrorist group.
Battling over taxes
Clinton hammered Trump over his refusal to release his tax returns.
"Why won't he release his tax returns?" Clinton asked.
"Maybe he is not as rich as he says he is," she went on. "Maybe he is not as charitable as he claims to be," "Maybe he doesn't want the American people to know that he has paid nothing in federal taxes."
Clinton pressed Trump on the issue, saying "There is something he is hiding."
Trump replied that he would release his taxes when Clinton made public 33,000 emails that were deleted from her private email server. When Clinton said that Trump had paid no federal income tax in some years, Trump replied "That makes me smart."
Clinton also set about Trump's business record, pointing out that he had called himself "The King of Debt" and accusing him of "stiffing" thousand of contractors who did work for his business.
When the debate turned to racial issues and crime, Clinton said that it was important for police to work together with local communities to restore trust.
Trump accused Clinton of refusing to say the phrase "law and order" and bemoaned the state of inner cities. He said that African-Americans and Hispanics were "living in hell."
"You walk down the street, you get shot," Trump said.
Clinton rebuked Trump for painting "such a dire picture" of black communities.
Campaign at a critical point
Trump and Clinton are facing off with the campaign at a critical point, as the race is a dead heat just 43 days before Election Day.
Under the relentless spotlight of the presidential debate stage, Trump faces his toughest examination yet of whether he has the knowledge and temperament to be president. Any gaffes or emotional eruptions by Trump could play into Clinton's claim he would be a dangerous risk in the Oval Office.
Clinton, meanwhile, faces the vexing assignment of fact-checking Trump's often outrageous statements while making an emotional connection with voters and building enthusiasm for her candidacy, especially among millennials.
Debate prep
The rivals spent the day preparing for their big battle.
Clinton participated in mock debates with her tart-tongued former aide Philippe Reines playing Trump. In one practice debate, Reines assumed the character of the unpredictable nominee by praising Clinton for her role as a pioneer for women, campaign sources said.
Reines even wore the kind of signature red tie that Trump favors and adopted his characteristic hand gestures in a bid to fully prepare Clinton for her unpredictable foe.
The Republican nominee has watched videos of Clinton, but his preparation has been less intense than his opponent's, in keeping with his more freewheeling style. He did not hold mock debates, for instance, with someone standing in for Clinton.
Latest polling
Latest polling shows the stakes for the debate are monumental.
A CNN/ORC poll released Monday found Trump edging Clinton 42% to 41% in the crucial battleground state of Colorado among likely voters in a four-way race. In Pennsylvania, another key state, the poll found Clinton in a virtual tie against Trump among likely voters at 45% to 44%.
The former secretary of state is relying on both states to help pave her way to the 270 electoral votes needed to win the White House.
Nationally, CNN's Poll of Polls finds Clinton and Trump neck-and-neck 44%-42%.
Political guests
Clinton and Trump are making political points with their choice of guests for the big event.
Clinton has invited billionaire businessman and prominent Trump critic Mark Cuban; 9/11 survivor Lauren Manning; Maxine Outerbridge, who benefited from a children's health insurance program the Democratic nominee backed as first lady; Anastasia Somoza, a disability rights advocate; and Aleatha Williams, her longtime pen pal.
Boxing promoter Don King, no stranger to big heavyweight fights, is in the audience and is backing Trump. The Republican invited two former members of the military brass who have backed his campaign, Lt. Gen. Michael Flynn and Lt. Gen. Keith Kellogg. He has given great seats to Karen Vaughn, who lost her Navy SEAL son in Afghanistan, and Mark Geist, a survivor of the attacks on a US compound in Benghazi, Libya, in 2012.
