Madison Keys came from a break down in both sets to defeat Svetlana Kuznetsova 7-5, 7-6 (7/5) on Sunday to win the WTA Cincinnati crown.
The 2017 US Open finalist notched her fifth career title and second this season after a win in Charleston in April.
She'll return to the top 10 in the world rankings with the US Open a week away.
Kuznetsova, a two-time Grand Slam champion working her way back up the rankings after a series of injuries, was broken back in the 10th game of each set by 16th-seeded Keys -- who fired 13 aces on the way to victory.
"If my team had told me a week ago that I would be here, I would have laughed in their face," admitted Keys, who had endured two opening-match defeats since a second-round exit at Wimbledon.
Keys belted a total of 43 winners with 33 unforced errors and broke Kuznetsova three times.
Kuznetsova was the fourth Grand Slam winner Keys beat during the week, a string that included Spain's Garbine Muguruza, reigning Wimbledon champion Simona Halep and Venus Williams.
"It was a tough draw from the very start," Keys said. "I definitely think I played some of my best tennis consistently this week.
I'm obviously really happy and really proud of myself," she added, while stressing she won't let the performance put more pressure on her at the US Open.
"It's definitely more of a building block," she said.
Despite leading both sets, Kuznetsova never had a set point in either, Keys winning the final four games of the first set before dropping her serve in the third game of the second.
Keys broke Kuznetsova to level at 5-all and ran out the winner in the ensuing tiebreaker as the Russian sent a service return long on Keys's second match point.
"I just really focused in on obviously really important games and was able to make her play a lot of balls," Keys said.
"I think when I was doing a good job at moving forward and kind of trying to neutralize some of her deep, heavy, spinny shots, I was able to get out in front in the point and play a little bit more offense."
Former world number two Kuznetsova, who received a wildcard into the draw, beat top seed Ashleigh Barty, world number three Ashleigh Barty and 2017 US Open champion Sloane Stephens on her way to the final.
"I had a lot of matches where they could have gone either way, including this one," said Kuznetsova, who will jump from 118th to 31st in the rankings and said she'd had a "great week."
"I had chances but she hit the ball well and was more aggressive. I'm happy with how I played, I'm feeling great," she said.
"It could give me more motivation in the future," Kuznetsova added. "I just want to rest and get ready for the Open."