Keys led 6-2, 4-2 in under an hour before the World No.10 started to pick up some momentum, breaking serve and holding to win back-to-back games for the first time in the match and level at 4-4.
After saving one match point in the 10th game, Kasatkina also had a game point of her own to level the match at 5-5, but ultimately the American proved too tough and secured her third straight sets victory in the pair's four career meetings.
The American has beaten the Chinese No.1 twice this season, but in the first three months of the year at the Australian Open and Qatar Total Open in Doha - well before Wang's tear through the Asian swing, pair of titles on home soil, and Top 30 debut.
"I've actually played her twice already this year, but I expect the match to be completely different this time around. She's had an incredible, like, six weeks, seven weeks. I think she's probably really high in confidence and feeling her game," said Keys.
"I'm probably not even going to watch the matches that I played her and more focus on the last couple of weeks for her and see what she's doing well and hopefully play well enough to get through."