South Korea's Kim Sei-young rolled in a long birdie putt at the 72nd hole on Sunday to win the LPGA Tour Championship and claim a record winner's prize of 1.5 million U.S. dollars.

Kim, leader after each of the first three rounds, struggled to build momentum at Tiburon Golf Club in Naples, Florida.

But she came through when it mattered, edging England's Charley Hull by one stroke.

She was one-under for the day through 17 and Hull had joined her atop the leaderboard at 17-under par with a bogey-free six-under 66 that included birdies at 16, 17 and 18.

A playoff looked more than possible, but Kim didn't blink, rolling in her fifth birdie of the day at the final hole to seal the win with a two-under par 70 for an 18-under par total of 270.

Kim said she had "no idea" that she was putting for the win at 18.

"Last putt I was just trying make two-putt because I didn't see the leaderboard," Kim said.

"I just tried to make the right distance; made it. It's unbelievable," she said. "I was, like, so emotional, almost crying."

Hull, who started the day five off the pace, said she knew after birdies at the second, 12 and 13 that she had a shot at the largest winner's check ever in women's golf.

"Kind of 15 I looked at the leaderboard and I thought I've got a chance," she said. "I didn't birdie 15, but I birdied 16, 17, 18 – I gave it my best shot."

Kim acknowledged that she was feeling the nerves – even though she was feeling the pressure not from Hull but from playing partner Nelly Korda.

"I didn't know Charley finished at 17 (under)," Kim said. "What if I couldn't make it? I could go to a playoff. It's not good for me."

Telling herself it was "no big deal," Kim said she "just tried to play like a practice round."

Even more than the prize money, Kim said, she was delighted to achieve her pre-season goal of adding a third title of the year to a resume that now includes 10 victories.

"That's the most satisfying," she said.

In the end her well-struck putt broke late and dived into the hole.

American Danielle Kang delivered a storming seven-under final round, highlighted by an eagle at 17, to share third place on 272 with Korda, who started the day two back and carded a one-under 71.

World number one Ko Jin-young finished tied for 11th, but still added to her haul of season-ending hardware.

The LPGA Player of the Year, whose four titles included two majors, also snagged the money title and the Vare Trophy for the lowest scoring average.

"I am honored to win amazing awards," said Ko, who came into the week nursing an ankle injury.

"I tried to do my best today, but putting was not good," she said, admitting it made for mixed feelings as the season ended.

"It's good, but my play was not good. So I will work harder," Ko said, adding it was "not the end" but "the beginning."