Korda and Minjee Lee both birdied the final hole of regulation to finish at 18-under 270 and force a playoff with Caroline Masson, who shot a 68.
Korda, who started the final round with a three-stroke lead over Lee (69), looked set to win in regulation after a birdie on the par-5 No. 12 gave her a three-shot lead. But she bogeyed three of her final five holes to fall one stroke back of Masson before a birdie on 18 gave her even-par 72.
“It just gets away from you so fast,” Korda said. “And Caroline made a couple putts and she was one ahead of me on 17. I was like, geez, I have to make a birdie here.”
Masson took the lead after back-to-back birdies on Nos. 15 and 16 but closed with par on the final two holes.
“I did have a couple chances to get maybe two ahead on 17 and make birdie on 18, and didn’t use them, but I think overall, I just hung with them all day,” Masson said. “Super proud of the way we played and battled.”
In the playoff on the par-5 18th, Korda was the only one to find the fairway and hit a perfect second shot to set up an eagle chance. She left the eagle putt short, but a birdie was enough for her to win her third career LPGA title.
With her second win of the year, Korda is the first American with multiple wins in the 2019 season.
Brooke Henderson of Smiths Falls, Ont., shot a 68 to finish regulation tied for fourth, four strokes back with South Koreans Sei Young Kim and Mi Jung Hur.
Hamilton’s Alena Sharp tied for 49th.