Amy Dorris, 48, told The Guardian she is coming forward now because she no longer wishes to remain quiet about the incident and wants to be a role model to her now teenage daughters.
Dorris said she attended the September 5 event in New York in 1997 with her then boyfriend, Jason Binn who was a friend of Trump.
She also provided The Guardian with evidence to support her account of her encounters with Trump, including her ticket to the US Open and six photos showing her with Trump over several days in New York.
The couple were joined by other friends of Trump who was 51 at the time, in his private VIP box. Dorris said the alleged assault occurred when she went to the bathroom and found him waiting outside when she came out.
“Initially I thought that he was waiting to go to the bathroom, but that wasn’t the case, unfortunately,” she said.
She alleges Trump forced himself on her after a brief exchange in which she recalls nervously laughing and telling him: “No, get away.”
Dorris, 24 at the time, says she told him “no, please stop” but “he didn’t care”.
“It doesn’t matter who you are,” she said. “Any time anyone says no, no means no. And that just didn’t work out for me. It wasn’t enough.
“He just shoved his tongue down my throat and I was pushing him off. And then that’s when his grip became tighter and his hands were very gropey and all over my butt, my breasts, my back, everything,” she said.
“I just kind of was in shock,” she added. “I felt violated, obviously. But I still wasn’t processing it and just was trying to go back to talking to everyone and having a good time because, I don’t know, I felt pressured to be that way.”
Following the alleged incident, Dorris and Binn attended several events with Trump in the days afterwards.
“I was there from Florida and I was with Jason. I had no money, nowhere to go. We were going from event to event and it was overwhelming.”
She did not fully process what had happened until later, she said. “People spend years around people who have abused them, that’s what happens when something traumatic happens, you freeze.”
According to the Guardian Dorris’ account of the alleged incident was backed up by several people she had talked to immediately afterwards.
Dorris said she wanted to be a role model for her teenage daughters as she shared her story.
“Now I feel like my girls are about to turn 13 years old and I want them to know that you don’t let anybody do anything to you that you don’t want,” she said.
Lawyers acting for Trump denied in the strongest possible way, that he ever harassed, abused or behaved improperly toward Dorris.
They said Jason Binn had told them he had no recollection of Dorris telling him that anything inappropriate had happened with Trump or that she felt uncomfortable in his presence.