NBC's widely respected evening news anchor earned a "C, C+" grade from the Republican candidate Donald Trump, who judged he had been asked "unfair" questions.
"I thought he was fine," Trump told on Fox News on Tuesday.
"I mean nothing outstanding. He gave me very unfair questions at the end."
The billionaire real estate mogul went on to complain bitterly that Holt had been too easy on his Democratic rival Hillary Clinton.
"He didn't ask her about the emails, he didn't ask her about the scandals, he didn't ask her about the Benghazi deal."
Holt's role had been the subject of widespread debate ahead of the event following an avalanche of criticism that fell on fellow NBC anchor Matt Lauer, whose job moderating a forum with both candidates earlier this month was lambasted for being unfair toward Clinton and easy on Trump.
Lester Holt during the debate (AAP) Source: AAP
Trump himself had praised the 57-year-old journalist as "a very good man" before the highly anticipated debate, watched by over 80 million people according to estimates cited by US media.
Was Holt's role to factcheck and call out lies, as many Democrats urged, or let the candidates prove their mettle by fighting their own fights?
"I'm honored to have this role, but the evening belongs to the candidates," he said, introducing himself at the start of the debate at Long Island's Hofstra University near New York.
Early on, Holt began letting the candidates speak beyond their allotted times, allowing the rivals to interrupt him or remaining silent for minutes at a time, leaving the opponents to go at each other.
He also failed to challenge several false assertions.
"CNN Launches Manhunt After Lester Holt Vanishes From Debate," The New Yorker magazine quipped in a parody piece during the debate.
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Giving candidates time
Others pointed out that Holt's approach gave the candidates time to show their personalities by expressing themselves.
And he did call out Trump several times, including when the Republican claimed to have opposed the US invasion of Iraq in 2003. "The record shows otherwise," he said.
Holt also questioned Trump about why he had not released his tax returns and asked Clinton about her use of a private email server when she was secretary of state.
He pressed Trump about his recent turnaround on the "birther" movement questioning whether President Barack Obama was born in the United States.
"For five years, you perpetuated a false claim," Holt said.
"Can you tell us what took you so long... I just want to get the answer here."
Those remarks did not please Rudy Giuliani, the former New York mayor and loyal Trump surrogate.
Holt should be "ashamed of himself," he told reporters after the debate.
"If I were Donald Trump, I wouldn't participate in another debate unless I was promised the journalist would act like a journalist and not an ignorant fact checker."
Two more presidential debates are scheduled for October 9 and 19.
They will be moderated by different journalists.
