While most of her rivals spent the week complaining of the notoriously soft and slow purple court, Barty went quietly about her business, dropping serve just three times in her four wins over world No.2 Karolina Pliskova, world No.6 Petra Kvitova, world No.7 Belinda Bencic and now the eighth-ranked Svitolina.
Barty finished the regular season with a WTA-best 15 wins over top-10 opponents as well as a tour-leading four titles from six finals, her latest success coming indoors having already picked up trophies on clay, grass and hard courts in 2019.
Throw in an equal-tour-high 55 wins from 67 matches and Barty is nothing less than a worthy year-end world No.1.
Barty had lost all five of her previous encounters with Svitolina, but emerged on a mission on Sunday night.
She dropped only five points in her first four service games before snaring the opening set with a booming forehand return winner down the line.
Barty dropped serve twice in the second set but, as champions do, broke back each time.
The match was all over after one hour and 27 minutes as Barty not only joined Williams and her mentor and idol Goolagong Cawley on the honour roll, but also fellow all-time greats Chris Evert, Martina Navratilova, Steffi Graf, Monica Seles, Justine Henin and Martina Hingis.
Barty’s record-setting pay day took her 2019 prize money haul to $US11.31 million ($A16.37 million), trebling her career earnings in 10 life-changing months.