She fought off a match point in the 10th game of the second set, crashing a forehand return off Davenport's second serve and going on to take the set and the match 5-7, 7-5, 6-4.
It was the 23-year-old American's 39th singles title of her career and her first since the 1996 Nichirei International, and she said: "To really pull it off feels great. I felt I was really fighting throughout the match, even when I was down those breaks, and for me the key is going to be consistency."
Defeat was a real anticlimax for Davenport, who had inflicted a rare defeat on Martina Hingis in a three-set semi-final. For Hingis, the 16- year-old Swiss who became the youngest woman to claim the world No 1 ranking on 31 March, it was only a second defeat his year.
"Sometimes you're just a human being," said Hingis, whose only other defeat of 1997 was to Iva Majoli in the French Open final. "Sometimes it's like a car, there's no more gas in there."
The men's world No 1 fared better. Pete Sampras beat Thomas Muster, of Austria, 6-3, 6-4 yesterday to win the ATP Championship in Mason, Ohio. His fifth title this year was the 49th ATP Tour victory of his career. That put Sampras alongside Boris Becker with the highest number of tournament titles among active players.