Six is certainly a magic number for U.S. Women's Open champion Jeongeun Lee6.

The 23-year-old South Korean won her first major title Sunday, the first $1 million women's winner's check ever handed out by the USGA and her first victory as an LPGA Tour rookie. And she did by shooting 1-under 70 at Country Club of Charleston to finish at, naturally, 6-under 278.

"This is kind of really interesting how I finished 6 under at an LPGA tournament," Lee6 said through an interpreter. "So, this is really lucky number to me."

Lee6 has the number in her name because she was the sixth player with the name on the Korean LPGA. She has embraced the number, answering to it and writing a large "6'' on her balls. Her South Korean fan club is called "Lucky 6." Jeongeun Lee5 tied for 34th at 4 over, 10 shots behind Lee6.

Lee6 opened a three-shot lead with three holes to play before facing some nerves with bogeys on the 16th and 18th holes to tighten things up. But when third-round co-leader Celine Boutier's blast from a greenside bunker on the 72nd hole rolled off the green, Lee6 had the biggest win of her life.

"I didn't even expect to win the tournament this fast," Lee6 said. "I think this is very lucky that I won this major championship tournament."

Lee6, playing two groups ahead of Boutier, was practicing putts when the Frenchwoman could not make the sand shot. Lee6 bent down in joy when her victory was secure, countrywoman and 2011 U.S. Women's Open winner So Yeon Ryu coming over to embrace the new champion.

"I felt pretty nervous starting on the holes 16, 17, and 18 after opening the large lead," Lee6 said. "But I tried the best that I can."

The victory came a few days after Tiger Woods' former swing coach, Hank Haney, made disparaging remarks about women's golf by predicting a "Korean" would win and "I'd go with Lee."

Haney was suspended for his comments on his PGA Tour SiriusXM radio show when asked who'd win. "I'd go with Lee," Haney said. "If I didn't have to name a first name, I'd get a bunch of them right." Haney was suspended for his remarks.

Haney sent Tweets on Sunday night congratulating Lee6 and saying his prediction was based on statistics and facts. "Korean women are absolutely dominating the LPGA Tour. If you asked me again, my answer would be the same but worded more carefully."

Lee6 said her focus had been fully on the tournament. Because she hasn't mastered English, "I didn't really understand him that much, so I didn't really think about it," she said.

Boutier made a double bogey on the final hole to fall into a tie for fifth at 3 under. She shot 75. Lexi Thompson, Ryu and Angel Yin tied for second, two shots behind. Thompson shot 73, Ryu 70 and Yin 68.

Boutier tried to get on No. 18 in two. "And then if I made the putt, then it would be best," she said. "But I missed the green, so ..."

Gerina Piller, Jaye Marie Green, Mamiko Higa of Japan, and third-round co-leaders Yu Liu of China and Boutier tied for fifth. Piller was the only under par at 68. Higa and Liu shot 74s.

Boutier and Liu, the good friends and former Duke teammates, figured to fight for the title. Instead, both threw away chances early as they combined for three bogeys and a double bogey on the first three holes.

Thompson began the round a shot off the lead in search for a second career major. But she too struggled early with bogeys on the first, third and fourth holes to drop off the pace.

"It was a bit of a rough day," Thompson said. "I got off to a pretty bad start. Just overall wasn't as comfortable, I guess, over my shots."

Lee6 is hardly a surprise winner. She came in ranked 17th in the world and has won six times on the KLPGA Tour. She tied for fifth in this event in her 2017 debut and has three top 10s on the LPGA Tour this season.

"So looking at her as a rookie to play this tournament so well, I'm really proud of her as a fellow competitor and same country girl as well," Ryu said.

Higa faded in the final round after being a major contender at her first U.S. Women's Open. She set the tournament mark for lowest debut with her opening 65. She was a stroke in front through 36 holes and only a shot behind when the final round began. But she had five bogeys on her first 13 holes to fall back. She finished tied for sixth after a 74.

NCAA women's individual champion Maria Fassi started her first tournament as a pro 72-73 to make the cut on the number. She took flight on the weekend, going 68-70 to tie for 12th with a group at 1 under that included the tournament's low amateur in Gina Kim, part of Duke's recent NCAA team champion.

Two-time major champion Lydia Ko had a hole-in-one Sunday — the only of the week — on the difficult 11th hole. She hit a 6-iron from 172 yards and, moments later, heard cheers up near the green, but wasn't sure why. She found out soon enough for her second career ace, the other coming at the Rio Olympics. The 11th, built with a false front and two large protective bunkers on each side, played as the hardest hole this week.