>> Read more trending news
"I really exceeded my own expectations for the show, so I don't feel bad about it," he told The New York Times.
He later commended Boettcher, 27, for her "world beating performance."
"There's no greater honor than knowing an opponent had to play a perfect game to defeat me," Holzhauer tweeted Monday night.
He also quipped: "To @KenJennings: You win this round. But if Jeopardy ever gives me 43 second chance games, look out!"
Boettcher cemented her victory with a $20,201 wager on the final clue: '"A great reckoning in a little room" in 'As You Like It' is usually taken to refer to this author's premature death." All three contestants gave the correct response, "Who is Marlowe?"
She said she didn't know about Holzhauer's streak until right before the filming of Monday's episode, which was recorded in March, the Times reported. Episodes featuring Holzhauer's streak began airing in April.
"When they said 32, I almost thought they were joking at first, just throwing out a random number, but it became clear during the game that he definitely earned it," Boettcher said in an interview shared from the show's Twitter account.
Boettcher, a Princeton grad who earned a Master of Library and Information Science from the University of North Carolina at Chapel Hill in 2016, is a longtime "Jeopardy!" enthusiast whose master's thesis focused on "predicting the difficulty of trivia questions," the Chicago Tribune reported.
"If someone had to end James Holzhauer's fantastic run, we're glad it was a #librarian," the American Library Association tweeted.