Ewart Shadoff went wire-to-wire at The Saticoy Club in California, but the final round felt more like a roller coaster.

The 34-year-old from England started with a four-shot lead, and that was gone by the time she made the turn.

She had to hold it together for pars on the closing three holes to win at 15-under from former US Women's Open champion Yuka Saso, who made an eagle and five birdies in a closing 66.

South Africa's Paula Reto led when Ewart Shadoff took bogey on the par-3 9th hole but she bogeyed the last two holes for a 69 to tie for third with England's Georgia Hall (65) and American Danielle Kang (67).

Youngster Karis Davidson (70) and Sarah Kemp (71) were the best of the Australians in a tie for 32nd at four-under, while Steph Kyriacou tumbled to T66 with a closing 77.

When Ewart Shadoff tapped in for par and victory the celebration was a mixture of tears and champagne that friends and players sprayed on her.

RIGHT: Ewart Shadoff finally poses with an LPGA Tour trophy. PHOTO: Meg Oliphant/Getty Images.

"That last one-footer felt like 20 feet to me," she said.

She becomes the 10th player this year to win for the first time on the LPGA Tour, one short of the record set in 1995. None of the others had to wait this long.

"It's a little bit surreal," said Ewart Shadoff, holding back tears. "I didn't know if this moment would ever come. I'm just really grateful for everybody who is on my team. Last year was really hard. I'm standing here because of them. I'm just really grateful."

"I learned that I could fight through adversity. I can play under the nerves, which it's been kind of a problem for me in the past, is just trying to settle the nerves down and play through it," she said.

"I think I proved to myself that I can do it. I proved I can win. It's been a long time, and like I could, I didn't think I would ever be sat here honestly. Just really grateful."

Atthaya Thitikul, the 19-year-old from Thailand, closed with a 68 and tied for eighth. It was her fourth consecutive top-10 finish on the LPGA Tour as she gets closer to reaching No.1 in the women's world ranking.