Pegula is one of the best players on the WTA Tour to have never won a major and the Buffalo, New York native's run to the final is all the more impressive given the injury setbacks she suffered earlier this year.
"If you would have told me at the beginning of the year I'd be in the finals of the US Open, I would have laughed so hard because that was where my head was. I was not thinking that I would be here," she told reporters.
"So to be able to overcome all those challenges and have a chance at the title on Saturday ... in my home country, in my home slam. It's perfect, really."
Standing in her way is the reigning two-time Australian Open champion Sabalenka, whose thunderous serve and punishing groundstrokes have overwhelmed her opponents at Flushing Meadows this year.
The second-seeded Belarusian is looking for redemption after letting last year's US Open final slip away to American Coco Gauff after winning the first set.
"Last year it was very tough experience, very tough lesson," she said.
"I wasn't ready. Then I got emotional. Then I just couldn't handle the crowd."
Sabalenka has won five of the pair's seven career meetings, most recently a straight-sets victory at the Cincinnati Open final, and said she expects another tough fight on Saturday.
"We had a lot of great battles in the past, really difficult, tight matches," she said.
"She's playing really incredible tennis. We played recently in Cincinnati and it was a really tough match. Even though I closed the match in two sets, still it wasn't that easy.
"She's playing her best tennis, I would say, and feels like she's back on track.
"Cannot wait to play against her."