"She's nasty," Trump told The New York Times in an interview published Friday night, "but I can be nastier than she ever can be."
The comments were part of a wide ranging interview in which Trump also touched upon his marriages, his recent late-night Twitter rant and his performance at the first presidential debate.
"Hillary Clinton was married to the single greatest abuser of women in the history of politics," Trump told The Times. "Hillary was an enabler, and she attacked the women who Bill Clinton mistreated afterward. I think it's a serious problem for them, and it's something that I'm considering talking about more in the near future."
Trump and his campaign, however, have repeatedly referenced Bill Clinton's infidelity this week. The Saturday before the debate, he threatened to bring Gennifer Flowers as a guest to the debate, and after Monday's event, he told CNN's Dana Bash he was "happy" he was able to refrain from mentioning "the indiscretions with respect to Bill Clinton."
On Wednesday, a copy of Trump campaign talking points instructed supporters to use figures like Flowers and Monica Lewinsky to counter criticism of Trump's treatment of a former Miss Universe.
Referring to Eric Trump's comments earlier in the week that Donald Trump showed "courage" in not bringing up the issue at the debate, Clinton spokesman Brian Fallon tweeted Friday night, "Assume (Eric Trump) now believes he's a coward."
He also told the Times that his own marriage history does not prevent him from being able to make attacks against the Clintons' relationship. Trump has been married three times, and his first marriage fell apart after he carried on an affair with Marla Maples.
Bill Clinton's infidelities, Trump said, "brought shame onto the presidency, and Hillary Clinton was there defending him all along."
The GOP presidential nominee told the paper that he believes the issue will worsen Hillary Clinton's likeability with female voters.
Asked if he ever cheated on his wives, Trump responded: "No — I never discuss it. I never discuss it. It was never a problem."
And when asked specifically about his affair with Maples, he responded, "I don't talk about it. I wasn't president of the United States. I don't talk about it. When you think of the fact that he was impeached, the country was in turmoil, turmoil, absolute turmoil. He lied with Monica Lewinsky and paid a massive penalty."
Trump also tore into Clinton's decision to feature Alicia Machado, a 1996 Miss Universe whom Trump allegedly called "Miss Piggy" and "Miss Housekeeping," as a surrogate. Machado has joined the Clinton campaign in publicly denouncing Trump's comments against women, and Trump has responded with smears against the former beauty queen during interviews and on Twitter, including shaming her for a sex tape for which the campaign has not provided evidence.
Trump told the Times he was "absolutely disgusted" that Clinton enlisted the help of Machado for her campaign and that Clinton, who has portrayed Machado as a victim, had "made this young lady into a girl scout when she was the exact opposite."
Looking ahead to the next debate, Trump said he's going to start preparing as early as this weekend. But he does not think that he needs to prepare more rigorously, blaming audio issues Monday with distracting him.
He "spent 50 percent of my thought process" dealing with it, Trump said.
And he backed away from his proclamation Monday that he would "absolutely" support Clinton if she won the election in November,
"We're going to have to see," Trump said. "We're going to see what happens. We're going to have to see."