American Madison Keys won the fifth title of her career by winning the Cincinnati U.S. Open final with a 7-5, 7-6 (7-5) victory.
Keys, 24 years, showed great determination after making up for her loss in both sets, and returned from a distance to her second title of the season, after the Charleston Tournament in April, her first on the dirt courts.
The 18th-ranked world number one will return to the top 10 on Monday as the Us Open approaches, the fourth grand slam to kick off August 26.
Kuznetsova, 34, the 2009 French Open and Us Open (2004), lost her 10th set to pave the way for the 2017 Flushing Meadows final, her best grand slam result, to win in an hour. And 44 minutes.
"If (my team) had told me a week ago that I would be here (to win the Cincinnati title), I would have laughed in their faces," said Keyes, who left the first round in the last two rounds after being knocked out of the second round at Wimbledon, the third major tournament.
The U.S. made 43 wins against 33 indirect fouls, breaking Kuznetsova's lead on three occasions.
The Russian, ranked 153rd in the world, is seeking to advance to the top of the standings after a series of injuries that kept her out of the competition.