Lydia Ko never won more in one day than on Sunday in the CME Group Tour Championship, where she claimed the richest prize in women’s golf at US$2 million with a victory that allowed her to win LPGA player of the year.

Ko outlasted Leona Maguire of Ireland in the final round, seizing control with a seven-foot birdie putt on the 16th hole and closing with two-under 70 for a two-shot victory.

Unflappable in a strong but occasional wind, Ko wiped away tears when she tapped in for par on the final at Tiburon Golf Club.

“There was a lot of things on the line today,” Ko said. “I really wanted to play the best golf I can. I knew it would be a tough battle, especially with how tough the conditions were.”

The 25-year-old Kiwi won her 19th LPGA title and third of the year to win the US$2m (NZ$3.25m) prize - the largest first place prize in the history of women’s sport.

It’s an early wedding gift as she now prepares to marry her fiancé in Korea during the off-season.

“I couldn’t have drawn it up any better. There’s been so many exciting things going on in my life. It will my last win as a single lady,” she joked.

 “This has been of the most consistent and solid years I’ve had. I’m excited my photo of winning here in 2014 with the glasses can get updated this year with the blue jacket,” Ko added referring to the new blue jacket which follows the tradition of the Masters men’s tournament where the winner gets the green jacket.

The US$2 million prize took her season earnings to just over US$4.3 million ($NZ6.99m), leaving her US$591 short of the Lorena Ochoa’s record for single-season earnings set in 2007. Ko clinched the points-based award for LPGA player of the year for the second time, and she won the Vare Trophy for the second straight year for having the lowest scoring average.

Player of the year and the Vare Trophy are each worth one point, along with the victory, giving her 25 points toward the 27 points needed for the LPGA Hall of Fame.

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The 25-year-old Kiwi, tied with Maguire at the start of the final round, took her first lead with a birdie on the par-3 eighth hole. Ko still led by one shot when she hit her tee shot just short of the flag on the par-3 16th and made the 7-foot birdie putt.

Ko two-putted from 25 feet for birdie on the par-5 17th to keep her lead at two shots going to the final hole, and she played it safe from there.

Ko finished at 17-under 271 and won the LPGA Tour finale for the second time. Her first title in the CME Group Tour Championship was in 2014 when she was 17 and already becoming a dominant figure in women’s golf.

Ko is on the verge of the LPGA Hall of Fame at age 25, a testament to how good she has been for so long.

“I’m glad the photo I won in 2014 with my glasses can be updated,” Ko said.

She ends the year with three victories — her first multiple-win season since 2016 — and had nine other finishes in the top five.

Maguire’s hopes began to fade when she hit a fairway metal so thin on the par-5 14th that it didn’t cross the hazard. She took a penalty drop, still couldn’t get to the green into the strong wind and had to get up-and-down with a wedge to salvage bogey.

Ko, however, hit her second shot off the side of a hill and into the hazard, and she also made bogey to keep the lead at one shot.

Maguire shot 72 to finish second. That was worth US$550,000 from the US$7 million purse. Anna Nordqvist had a 67 to finish third.

Ko now has 19 career victories — the first one was 10 years ago in Canada when she was a 15-year-old amateur, making her the youngest to win an LPGA Tour event.

“I felt more calmer than I thought I would be which was more worrying,” Ko said after her victory.

“There was a lot of things on the line today. I wanted to play the best golf I could today and there was so many big names chasing Leona and I. I knew it would be a tough battle, especially with the conditions as well.”

Ko previously won the season-ending event in 2014 and her last player of the year award came a year later. It caps off an impressive comeback to the top after struggling with form and going without a win for almost three years before claiming the Lotte Championship last April.

Lydia Ko is one round away from clinching LPGA player of the year and taking home the largest prize in the history of women’s golf.

Leona Maguire showed Saturday that it won’t be easy.

Maguire had four straight birdies around the turn, added a pair of birdies late and had a 9-under 63, allowing her to make up a seven-shot deficit and tie Ko going into the final day of the CME Group Tour Championship.

“The hole was looking big, and I was trying to hit it as close as I could,” Maguire said.

Ko had a five-shot lead to start the third round — seven shots ahead of Maguire — and made a mixture of birdies and bogeys that stalled her round. She fell one shot behind Maguire until chipping to tap-in range on the par-5 17th. She finished with a 70.

Maguire is too far back to win player of the year. There’s a lot more at stake than that.

“Obviously, the $2 million, it’s a lot of money,” said Maguire, who has made $1,262,831 in 23 tournaments this year on the LPGA. “We’re very lucky to be playing for that kind of money. So, yeah, try to make the most of the opportunity tomorrow.”

They were at 15-under 201 in what shaped up as a two-player race. No one else was closer than five shots to them. Former U.S. Women’s Open champion Jeongeun Lee6 had a 68 and Gemma Dryburgh of Scotland had a 69. They were at 206.

“It’s never over until that last putt drops for every single player, and I don’t think you can count anybody out,” Ko said. “Clearly the last three days have shown that somebody has shot a really low score. So who knows how far back you are for still be in contention.

“I just want to play golf that I don’t regret, golf that I feel confident and come at the end of tomorrow and say, ‘Hey, you know, I did my best.’ And this is where I finish.”

Adding to the pressure is the Sunday forecast for rain and 20 mph (32 kph) gusts.

“Nothing I’m not used to from Ireland,” Maguire said when she finished her round. “We’ll see where Lydia gets at the end of the day, but ultimately just go out and play as well as I possibly can, and especially if there’s bad weather, that’s all you can control. Looking forward to one last walk of the season tomorrow.”

Brooke Henderson kept her slim hopes alive for player of the year. The Canadian, who had to withdraw last week with a back injury, had two eagles in her round of 65 and was at 9-under 207.

Henderson will have to win the CME Group Tour Championship and have Ko finish third or worse to win player of the year.

“If I could have another day like this tomorrow, that would be really nice,” she said.

Ko came into the week with a one-point advantage over Minjee Lee for player of the year. Lee, the Australian who won the U.S. Women’s Open and leads the LPGA money list, has fallen nine shots behind and is all but certain to be eliminated.

Ko is a lock to win the Vare Trophy for having the lowest scoring average. A victory would send her season earnings to over $4.3 million.

Nelly Korda, who won last week at Pelican Golf Club, had to birdie her last three holes for a 73 that left her nine shots out of the lead.