O'Brien -- who graduated from the University of Pennsylvania's Wharton School of Business -- kept the incident a secret until now, when she told her story in a New York Times essay.
The now-40-year-old writer says she had just graduated from Notre Dame and was working as a (mostly high school) sports reporter for "The Fort Worth Star-Telegram" in 2002.
She was in a hotel room with an interview subject for a longer piece on foreign-born athletes in the U.S., when things took a frightening turn.
"We spoke for a few minutes as I asked some questions and he answered," writes O'Brien, who did not identify the athlete.
"Then he moved suddenly to kiss me. I said, no, no, I don’t want that, but he pushed me over to the bed. I tried to shove him. I said no, stop, no, stop, over and over.
"He pushed further, getting on top of me, pulling off my skirt and having sex with me against my will."
O'Brien felt as if she told anyone, her career would be ruined.
And so, she kept this secret for years, back and forth between blaming herself and telling herself it never happened.
It wasn't until last January, O'Brien says, when NY Mets General manager Jared Porter was fired for sending sexually explicit texts and pictures to a female reporter in 2016, that she started to think of her own experience.
“I hadn’t been a sports reporter in 11 years, but as I read accounts of other women’s experiences with sexual harassment, the full force of my own assault hit me,” she said.
“And with it came the relief that I actually hadn’t invited it, hadn’t done anything wrong at all, something I had never once considered.”
Click here for O'Brien's complete essay in The New York Times.
Click here to follow Daily Voice Middletown-Wallkill and receive free news updates.