France's Caroline Garcia created history with victory in the women's final at the Western and Southern Open in Cincinnati.
It is Garcia's third career Masters trophy after back-to-back wins in Wuhan and Beijing almost five years ago.
The world number 35 is now set to return to the top 20 rankings for the first time since 2017.
After getting through qualifying, Garcia beat three top-10-ranked opponents in Maria Sakkari, Aryna Sabalenka and Jessica Pegula, before another superb performance against Czech two-time Wimbledon champion Kvitova.
No qualifier has won a WTA 1000 title since the tier was created in 2009.