Second seed Garbine Muguruza claimed her second title of the year after recovering from a set down to win the inaugural Chicago Fall Classic.
The Spanish former world number one came through 3-6 6-3 6-0 against Ons Jabeur of Tunisia, the sixth seed.
Muguruza was outplayed in the first set and then lost her serve twice early in the second to be in real trouble.
But she managed to regroup and as she got stronger, Jabeur, the world number 16, started to struggle.
Muguruza reached the final after a walkover in her semi-final when Czech Marketa Vondrousova, the Tokyo Olympic runner-up, pulled out with an injury.