She tapped in for a birdie that was matched by Maguire, while defending champion Korda managed only par and was eliminated in the playoff.
“I think this one is even better than the first personally,” Kupcho told the LPGA afterwards. “I had such a big lead going into the last round at Chevron, so to come out here with top players all over the place, the standings was full, in strokes, so it was very close, and I’m very proud of myself because I got out.
“I thought to myself this morning that I should call (my father) but I kept saying to myself, ‘No, we’ll call him after the round with the trophy in our hand’, and I’m excited to be able to do that now. “
The playoff ended a rollercoaster ride for Kupcho on the last day after she mapped an early double bogey on the third hole and a bogey on the sixth, falling three shots behind overnight leader Korda. An eagle on the eighth and a birdie on the ninth reversed the damage before birdies on the 12th and 14th propelled her into the lead.
“I had a little trouble at the beginning, so it tells me I can really come back from it,” Kupcho said, according to ESPN. “I’ve always known I’m a back-nine player and that definitely took effect today.”
Playing in a group for the American pair, Maguire came into battle with 65 cards on her final round to close the seven-shot gap that had separated her from the overnight lead.
She birdied the last hole to set the benchmark at 18 under par.
Korda also birdied the final hole as Kupcho settled for par after her drive found a bunker, putting all three players at the top of the leaderboard for the playoff.
“If you told me that I think three or four months ago when I was in the emergency room that I would be here, I would be very happy.”