PEBBLE BEACH, California: Allisen Corpuz became the first American in 20 years to make the US Women’s Open her first LPGA title, closing with a 3-under 69 on Sunday and handling her historic moment at Pebble Beach as if she had been there before.

Corpuz, a 25-year-old from Hawaii, pulled away with a big par putt and back-to-back birdies on the back nine to enjoy the most scenic walk in golf up the 18th fairway, the Pacific Ocean on her left and her place secured as the first US Women’s Open champion at Pebble Beach.

She won by three shots over Charley Hull (66) and Jiyai Shin (68) and claimed the $2 million prize, the richest ever for an LPGA major champion.

Corpuz was so calm and cool on the grandest stage in women’s golf, regardless of the shot or the circumstances, until reality began to set in down the 18th, the same path walked by Jack Nicklaus, Tom Watson and Tiger Woods, all Open champions at Pebble Beach.

When she tapped in for par, she covered her smile with her hand and wiped tears away with her Aloha-print towel.

“Unreal,” Corpuz said. “This week has felt like a dream come true. It’s been really awesome to be at Pebble Beach this week. Every few holes I kind of looked out and thought, ‘I’m here at Pebble. There’s not many places better than this.’”

Former President Barack Obama was among the first to congratulate her on Twitter. Both went to Punahou School in Honolulu.

“You make us all proud — and look forward to a round at Kapolei!,” Obama tweeted.

Hilary Lunke in 2003 at Pumpkin Ridge was the last American to get her first win at the US Women’s Open, that one in a three-way Monday playoff.

Corpuz, who finished at 9-under 279, was the only player to break par all four days.

Corpuz never gave anyone much of a chance. Nasa Hataoka lost her one-shot lead on the opening hole when Corpuz hit her approach to 5 feet for birdie, and the 24-year-old from Japan dropped too many shots down the home stretch.

They were tied at the turn until Corpuz hit her approach to just inside 10 feet for birdie on the 10th. The key moment came at the par-3 12th, when Corpuz hit her approach short into the bunker and had 15 feet for par. Hataoka rolled her birdie putt from the fringe 5 feet by the hole. Corpuz made her par, Hataoka missed her putt and the lead was at two.

It only got larger, Corpuz stretching it to four shots with superb wedges to 8 feet on the par-5 14th and 4 feet on the 15th, both birdies that made the final act a battle for second place.

Hull, who started the final round seven shots behind, closed to within two shots early on the back nine and stayed in the game with a 30-foot birdie putt on the 16th. Only later did she realize Corpuz was pulling away. Hull kept firing, hitting 3-wood from under the cypress tree in the middle of the 18th fairway and nearly pulling it off.

“Shy kids don’t get sweets,” she told herself on the 18th before lashing away and dropping to a knee to watch its flight.

Shin made a birdie on the 18th to join Hull as a runner-up.

Hataoka, whose 66 on Saturday was nearly nine shots better than the field, had a 40 on the back nine and tied for fourth with Bailey Tardy, the 36-hole leader who went 75-73 on the weekend for her best finish in her LPGA rookie season.

But this moment was all about Corpuz. She joined Michelle Wie West as the only major champions from Hawaii — Wie West won the Women’s Open at Pinehurst No. 2 in 2014 and played her final major this week at Pebble Beach.

They are not close except for their high school (Punahou) and education — Wie West graduated from Stanford, Corpuz got a business degree and an MBA from USC — and their early start.

Corpuz broke Wie West’s record as the youngest player to qualify for the US Women’s Amateur Public Links as a 10-year-old. This was her 19th USGA championship. She knows the USGA formula of fairways and greens, and loads of patience.

She is built for this, especially given her concentration that not even a gorgeous day on the Monterey Peninsula could crack.

Officiating behind the fifth green was Mary Bea Porter King, the pioneer of junior golf in Hawaii and one of the most influential figures in the game. Corpuz first came into the Hawaii junior program at age 7.

“She’s always been calm, cool and ... I won’t say serious, but she just plodded along. She was sort of a giant killer,” Porter King said. “I don’t think she was fearful of anything.”

That much was obvious at Pebble Beach, which had enough wind to be challenging as ever. Only seven players finished under par.

Rose Zhang, who dominated the amateur scene and then won her first LPGA Tour start as a pro, never got on track and closed with a 72 to tie for ninth. She now has top 10s in both majors as a pro, though this time she was never in the mix.