Hillary Clinton suggested a few reasons why Donald Trump is not releasing his tax returns during the first presidential debate, mainly saying, "maybe he’s not as rich as he says he is." (The Washington Post)

Hillary Clinton’s weapon of choice in her first debate with Donald Trump was a needle.

Almost from the outset of the 95-minute debate, the Democratic nominee, who is known for having a debate-stage persona as a policy wonk, took after her opponent with digs aimed at piercing his famously thin skin.

She began with one at the very core of his identity as a self-made success story. “He started his business with $14 million, borrowed from his father,” Clinton said in one of their early exchanges.

“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,” Trump protested.

Nimble is not a word often associated with Clinton. But the former secretary of state kept up the jabs and the footwork, taking a far more aggressive stance than she had demonstrated in the many past debates in which she has participated as a candidate for the Senate and for the White House.

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)

She seemed determined to create a contrast in tone and temperament, attacking Trump while smiling, mocking the claims of which he is proudest.

Clinton came to the debate stage with an imperative to shake up the dynamic of the race. The polls have tightened, and they indicate that Trump’s supporters are more enthusiastic about their candidate than Clinton’s are.

That they found themselves side by side on that stage marked a culmination of a remarkable political season. It was the first female nominee of a major political party at one lectern; at the other, an outsider who has overturned his political party, vanquishing a large field of heavily credentialed competitors in the GOP primaries.

Trump appeared thrown off balance by Clinton’s frequent needling, and at times he shouted back at her.

But she persisted, baiting the real estate mogul again and again.

She noted that Trump had rooted for the housing crash in 2006, seeing it as a business opportunity. She claimed that “Donald thinks that climate change is a hoax perpetrated by the Chinese.”

The true, the false and everything in between.

When moderator Lester Holt pressed Trump on his refusal to release his tax returns, Clinton struck again.

“You’ve got to ask yourself, why won’t he release his tax returns? And I think there may be a couple of reasons. First, maybe he’s not as rich as he says he is. Second, maybe he’s not as charitable as he claims to be,” Clinton said.

“Third, we don’t know all of his business dealings, but we have been told through investigative reporting that he owes about $650 million to Wall Street and foreign banks,” she continued. “Or maybe he doesn’t want the American people, all of you watching tonight, to know that he’s paid nothing in federal taxes.”

Clinton was determined to turn the tables on Trump, who earned a reputation for staying on offense during the long season of Republican primary debates.

While Trump was clearly annoyed at her many digs, he did not erupt, as she might have hoped he would.

And early on, Trump had her on the defensive at times, as he attacked her for shifting her stance on trade.

He said she had softened her advocacy of free trade only after he began emphasizing the ways in which current treaties — including the North American Free Trade Agreement, signed by her husband Bill Clinton — had hurt American workers.

That was also an argument that resonates with the Democratic base.

“I think my husband did a pretty good job in the 1990s,” Clinton said.

“He approved NAFTA, which is the single worst trade deal ever approved in this country,” Trump said.

The Republican nominee claimed that he has a superior temperament to hers — a statement that may in fact have been a misstep, because it reminded debate viewers of the quality of Trump about which they have the greatest misgivings.

It also gave Clinton an opening to use one of her favorite lines from the campaign trail: “A man who can be provoked by a tweet should not have his finger anywhere near the nuclear codes.”

Trump tried to sidestep the tripwire of sexism when Holt asked him about a comment he had made that Clinton did not have a “presidential look.”

“She doesn’t have the look. She doesn’t have the stamina,” Trump said.

Clinton charged in: “He tried to switch from looks to stamina, but this is a man who has called women pigs, slobs and dogs.”

Pre-debate polls indicated that most Americans believed that Clinton would do a better job than Trump in the first debate. So her camp engaged in an active campaign to even the expectations, demand that the media aggressively call out Trump’s untruthful statements and generate a groundswell of approval for her performance on social media.

That included coaching supporters via email to employ specific Twitter hashtags: “When Trump says something that makes you cringe: #LoveTrumpsHate” and “When Hillary say something that makes you proud: #ImWithHer.”

But the other side was also priming the perceptions pump with a dose of vitriol. Rep. Steve King (R-Iowa), a Trump supporter, tweeted early Monday afternoon: “Tonight’s biggest post #debate question: Inquiring American minds will want to know, was Hillary on her meds or off her meds?”

It was an apparent reference to a rumor campaign, being fueled by her detractors, that Clinton has health problems that undermine her fitness to be president.

Trump’s comments about Clinton’s stamina gave her an opportunity to cite her own record as a response and contrast.

“As soon as he travels to 112 countries and negotiates a peace deal, a cease-fire, a release of dissidents and opening of new opportunities in nations around the world, or even spends 11 hours testifying in front of a congressional committee, he can talk to me about stamina,” she said.

Anne Gearan contributed to this report.