"Nao and I have played a lot of times, and I always love playing her, we have a good time," said the Australian in her on-court interview.
That familiarity told as Barty put pressure on her opponent's serve from the off, demonstrating the confidence built from dropping only a single set over the course of the week.
After an hour and 13 minutes, the 20-year-old had the chance to serve it out - and did so to love.
? WTA (@WTA) March 5, 2017
"I'm over the moon, I don't really know what to say, I'm a bit speechless," she added afterwards.
Barty now pairs up with best friend Casey Dellacqua for the doubles final against Nicole Melichar and Makoto Ninomiya.
"It's been a massive week, a big week with a lot of matches," she said. "Now I have to try and recover as best as I can, and play some doubles soon."