Ally Ewing made five consecutive birdies on the back nine on Sunday and held off China's Lin Xiyu to win the Queen City Championship for her third career LPGA title.
The 29-year-old American fired a bogey-free final-round six-under par 66 to finish on 22-under 266 at a rain-softened Kenwood Country Club in Cincinnati, Ohio.
Lin birdied four of the last seven holes in shooting 65 and kept the pressure on Ewing to the final hole before losing by a stroke.
Ewing birdied the 12th through 16th holes to seize a two-stroke edge then matched pars with Lin at 17.
Short of the green at 18, Ewing missed her first green in regulation of the day while Lin gave herself a birdie 15-foot putt.
Ewing rolled a putt within three feet of the hole, but Lin answered by curling in her third birdie putt of the week at 18, only for Ewing to tap in for par and the victory, a smile and fist pump followed by tears of joy.
"I struggled with nerves all day because I just haven't been able to put this all together for a full tournament this year," Ewing said. "So to see it and see all the results finally come into place, it's really exciting."
World number 52 Ewing, who had not previously managed a top-10 finish all season, cracked $3 million in career earnings.
Ewing won for the third season in a row after taking the 2020 Drive On Championship at Lake Oconee and 2021 LPGA Match Play.
"The key for me has been just knowing it's in there," Ewing said.
"In Canada (two weeks ago), I was really close to putting some stuff together but it was a little finicky.
"This week I saw putts go in and once I saw them go in I had that confidence."
Mexico's Maria Fassi was third on 272 after a closing 71 with South Korean Lee6 Jeong-eun fourth on 274.
Lin missed out on her first title in her 189th tour event as she tries to become the second Chinese player to win an LPGA title after Feng Shanshan.
"It was another really good day," Lin said. "I did whatever I could do. I put one of the best rounds I've played this year out here.
"Come out second, which is a little sad, but Ally also played so well so congrats to her."
Lin seized the lead with birdies on three of the first seven holes but Ewing birdied the ninth to match Lin for the lead at 17-under as they made the turn in the last group.
"That calmed me down," Ewing said of holing her first birdie putt.
Fassi, who stumbled with two bogeys on the front nine, began the back nine with three consecutive birdies to pull two shy of the co-leaders.
Lin and Ewing both birdied the par-4 13th to stay deadlocked at the top, but Ewing rolled in her third birdie in a row at the par-3 14th to reclaim the solo lead.
Ewing then sank her fourth birdie putt in a row to reach 21-under and boost her lead to two strokes with three holes remaining.
Lin curled in a tricky birdie putt at the 16th but Ewing answered with her fifth consecutive birdie, setting the stage for the closing drama.