Donald J. Trump lashed out on Tuesday in the aftermath of a disappointing first debate with Hillary Clinton, scolding the moderator, criticizing a beauty pageant winner for her physique and raising the prospect of an all-out attack on Bill Clinton’s marital infidelities in the final stretch of the campaign.

Having worked assiduously in recent weeks to cultivate a more disciplined demeanor on the campaign trail, Mr. Trump cast aside that approach on Tuesday morning. As Mrs. Clinton embarked on an ebullient campaign swing through North Carolina, aiming to press her newfound advantage, Mr. Trump vented his grievances in full public view.

Sounding weary and impatient as he called into a Fox News program, Mr. Trump criticized Lester Holt, the NBC News anchor, for asking “unfair questions” during the debate Monday evening, and speculated that someone might have tampered with his microphone. Mr. Trump repeated his charge that Mrs. Clinton lacked the “stamina” to be president, a claim critics have described as sexist, and suggested that in the future he might raise Mr. Clinton’s past indiscretions.

Defying conventions of political civility, Mr. Trump leveled cutting criticism at a beauty pageant winner, Alicia Machado, whom Mrs. Clinton held up in Monday night’s debate as an example of Mr. Trump’s disrespect for women.