Donald Trump relentlessly attacked Hillary Clinton over trade and her private email server during their fiery first debate Monday night, often brusquely interrupting her, while Clinton portrayed Trump as unqualified for the presidency and lacking facts to back up his arguments.

After initially approaching Clinton with uncharacteristic restraint, Trump confronted her aggressively. He noted that her husband, Bill Clinton, signed the North American Free Trade Agreement into law and accused her of wanting to approve the Trans-Pacific Partnership.

“NAFTA is the worst trade deal ever signed everywhere,” Trump said, invoking a pact that is deeply unpopular in several swing states, and then added that the Trans-Pacific Partnership “will be almost as bad.” After Clinton said she had opposed the trade deal, Trump interjected and, raising his voice, talked over her.

“You called it the gold standard,” he said, nearly shouting.

Clinton, in a measured tone and with a tight smile, responded with a harsh rejoinder of her own. “Donald, I know you live in your own reality, but that is not the facts,” she said.

Trump hurled so many accusations at Clinton — and with such fervor that he frequently had to sip water — that she found herself saying at one point, “I have a feeling that by the end of this evening, I’m going to be blamed for everything that’s ever happened.”

Clinton got off to a confident start: Asked by the moderator, Lester Holt, why she would be better at creating jobs, she said she would support small businesses, working parents, equal pay for women and paid family leave. Trump was steady as well, sounding familiar themes about cutting taxes and stopping auto manufacturers and other companies from moving jobs overseas.

A revealing moment for Trump came when Holt asked him why he would not release his tax returns, as other presidential candidates have done for four decades. “I don’t mind releasing — I’m under a routine audit,” Trump said, then insisted that his financial disclosure form was available to the public, even though it lacks extensive details. Holt pressed him, saying that he was allowed to release his returns even under audit. Trump dodged the question.

Clinton seized on the issue of Trump’s taxes. “It must be something really important, even terrible, that he’s trying to hide,” she said.

Trump quickly criticized Clinton for using a private email server as secretary of state.

“I made a mistake using a private email,” Clinton said.

Trump would not let it go. “That was more than a mistake — that was done purposely,” he said. “When you have your staff taking the Fifth Amendment, taking the Fifth, so they’re not prosecuted, when you have the man that set up the illegal server taking the Fifth, I think it’s disgraceful.”