Brady, from Boca Raton, Fla., was a 6-4, 7-5 winner over fifth-seeded Lynn Chi of Cal. In the bottom half of the singles draw, sixth-seeded Zoe Scandalis of USC downed third-seeded Anett Schutting, 6-3, 6-3.
Brady and Scandalis will play for the title on Sunday at 10:00 a.m. at Libbey Park. That match can be seen live on the Pac-12 Networks.
Brady, who has yet to drop a set in four matches heading into the final, is aiming to become the second UCLA freshman in as many years to win a singles championship in Ojai, following 2013 winner Kyle McPhillips.
UCLA's Courtney Dolehide and Chanelle Van Nguyen were defeated in the semifinals of the women's doubles draw on Saturday, suffering an 8-2 loss to USC's Kaitlyn Christian and Giuliana Olmos.
More information about the Pac-12 Championships can be found at www.ojaitourney.org