Republican presidential nominee Donald Trump had a case of the sniffles during the first presidential debate on Sept. 26 – so we put them all in one supercut, with a few of his interruptions for good measure. (Gillian Brockell/The Washington Post)

Republican presidential nominee Donald Trump had a case of the sniffles during the first presidential debate on Sept. 26 – so we put them all in one supercut, with a few of his interruptions for good measure. (Gillian Brockell/The Washington Post)

The greatest mystery heading into the first presidential debate here at Hofstra University was which version of the unpredictable Republican candidate would show up for his first one-on-one face-off with Democratic rival Hillary Clinton.

The answer is, two versions of Donald Trump did.

Early on, he was relatively subdued, listening as Clinton spoke and even acknowledging a few points of agreement with her. The questioning and his answers were focused on issues that have helped propel his candidacy, including his condemnation of trade deals, his vow to bring back manufacturing jobs and sharp criticism of Clinton’s handling of her private email server.

But starting around the 11-minute mark in the 95-minute event, Trump’s cool began to melt. He started to shout through Clinton’s answers, gripping the sides of the lectern until his hands turned red.

“That’s called business, by the way,” Trump snipped early on, as Clinton accused him of rooting for the housing collapse.

Here are the highlights from Donald Trump and Hillary Clinton sparring over the Republican nominee's history with questioning President Obama's place of birth. (The Washington Post)

“I did not! I did not! I do not say that,” he shouted as Clinton accused him of calling climate change a hoax, which he has said on numerous occasions.

“Facts!” he yelled as Clinton began to question the accuracy of his assertions.

“Wrong! Wrong!” he said as Clinton stated that he initially supported the Iraq War, which he had.

“Where did you find it? Oh really?” Trump said as Clinton referred to a beauty pageant contestant who has accused Trump of calling her “Miss Housekeeping” because she is Latina.

And as Clinton criticized Trump for painting the African American community with a broad brush of stereotypes, Trump could be heard sighing.

[Winners and losers from the first presidential debate]

Trump — who has raised questions about Clinton’s health after her recent bout of pneumonia — appeared to have a cold and loudly sniffled through much of the debate. The Democratic National Committee issued a news release about Trump refusing to release his tax returns, with the headline “Trump Sniffs at Paying Taxes.”

Here are the key moments from the first 2016 presidential debate between Hillary Clinton and Donald Trump on Sept. 26. NBC Nightly News anchor Lester Holt moderated the debate at Hofstra University in New York. (Sarah Parnass/The Washington Post)

Trump came into the first debate the strongest that he has been in months, having caught up with Clinton in several national polls and passed her in some key battleground states. He underwent far more preparation for this debate than he ever admitted to doing during the primaries — but his aides and surrogates kept the details quiet and tried to play down expectations.

Former House Speaker Newt Gingrich — one of Trump’s advisers — tweeted out a low-bar prediction for the night: “@realdonaldtrump will pass the test of being adequately competent & will get a big boost in acceptability.”

The debate was held at Hofstra, a private college on Long Island that on Monday became a microcosm of the sharply divided nation. Trump has found bursts of support in the working-class neighborhoods here, just a short helicopter ride from the luxurious Manhattan skyscraper where he has long lived and worked, but the campus itself is a hotbed of the political correctness that Trump has long mocked.

[Fact-checking 23 claims made during the first presidential debate]

Hours before the debate, a swarm of Trump supporters gathered around an outdoor Fox News set and loudly chanted an attack on Clinton: “Lock her up! Lock her up!” At the other side of the parking lot, a quieter crowd of Clinton supporters stood around an MSNBC set, holding up a giant blue sign reading: “Stronger together.”

The debate began with a warm handshake, as Clinton said loud enough for the cameras to hear: “How are you, Donald?”

“Donald” is a first name that few use in Trump Tower, where even high-level employees and top aides usually address the candidate as “Mr. Trump.” The casual greeting seemed to annoy Trump, who asked Clinton if he could call her “Secretary Clinton.”

“Is that okay?” Trump said, with courtesy that seemed forced. “Good. I want you to be very happy. It’s very important to me.”

Clinton took the first clear swing of the debate, questioning Trump’s “trumped-up trickle-down” tax plan and reminding viewers of the money that Trump’s father lent him as he got started in business.

[Clinton goes after Trump’s weakness: His famously thin skin]

On the campaign trail for the past year, Trump has become the most defensive when his business decisions are questioned or attacked, a sensitivity that Clinton hit again and again, often prompting Trump to provide responses that will probably appear in attack ads in the coming weeks.

On that loan from his father, Trump responded: “My father gave me a very small loan in 1975, and I built it into a company that’s worth many, many billions of dollars, with some of the greatest assets in the world, and I say that only because that’s the kind of thinking that our country needs.”

When Clinton accused him of not paying people who completed work for him, including an architect she invited to the debate, Trump responded: “Maybe he didn’t do a good job, and I was not satisfied with his work.”

Trump — the first presidential candidate in 40 years to refuse to release his tax returns — continued to claim that nothing new could be learned from releasing them after Clinton said he had something to hide. He offered to release the documents if Clinton offered up emails from her server that were deemed personal.

As the debate entered its second half, Clinton stood by and listened during several episodes that may not have been helpful for him. He argued incorrectly and at length that New York City’s “stop-and-frisk” policing had not been ruled unconstitutional; he bragged that he had successfully prompted President Obama to produce his birth certificate as part of his long-standing “birther” crusade; and he insisted against evidence that he had always opposed the Iraq War, pointing to private conversations with booster Sean Hannity of Fox News as proof.

As he wrapped up the latter rant, which lasted several minutes, Trump plugged his own temperament.

“I think my strongest asset, maybe by far, is my temperament,” he said. “I have a winning temperament. I know how to win. She does not.”

In the final minutes of the debate, Trump and Clinton seemed to unload their remaining attacks on one another, although he never mentioned a comment that she made at a fundraiser about “half” of his supporters being “deplorables.” As Clinton listed comments that Trump made about women, he said that he chose not to air attack ads going after her personal life.

And when given the opportunity to explain at the end why he doesn’t think Clinton has the “look” for the presidency, Trump doubled down on his controversial comment, which GOP operatives say could hurt his chances at winning over white women with college degrees.

“She doesn’t have the look,” Trump said. “She doesn’t have the stamina. I said she doesn’t have the stamina — and I don’t believe she has the stamina to be president of this country.”