Thailand's Ariya Jutanugarn closed with back-to-back birdies to win the season-ending LPGA Tour Championship on Sunday, while American Lexi Thompson took the $1 million season bonus prize despite a last-hole heartbreak.

Ariya birdied four of the last six holes, sinking a 20-foot birdie putt on the 17th and a 23-footer at 18, to shoot a final-round five-under par 67 and finish 15-under overall at Tiburon Golf Club in Florida.

"My caddie told me to look at the leaderboard so I did and I was like, 'Oh shoot I need to make this putt," Ariya said of her closing dramatics.

"I was so nervous my hands were shaking and I started crying after I made it."

Thompson and compatriot Jessica Korda shared second, just one stroke adrift, with Sweden's Pernilla Lindberg and South Korean Ji Eun-Hee tied for fourth a shot further back.

It appeared Thompson would take the title, needing only a two-foot tap-in par putt at 18 to reach the clubhouse on what proved to be the winning score.

But the world number four missed, the ball lipping off the right edge, as she settled for the Race to the Globe season bonus prize.

"I guess it was just adrenaline with missing that putt because I didn't look at a leaderboard all day," Thompson said.

Ariya, meanwhile, joined the leaders on the penultimate green, then topped her feat with only the fourth birdie of the day at the last for the title.

It was the 2016 British Open champion's seventh career LPGA title and her second of the year after the Manulife Classic in June.

She plans to take the $500,000 winner's check to Asia and celebrate her 22nd birthday on Thursday.

"I'm going back to Thailand to spend my birthday with my family," Ariya said.

Thompson was the top finisher among the five players who could have ensured the $1 million by winning in Naples, the rich prize soothing the sting of defeat.

"It definitely eases it," Thompson said. "It's definitely not the way I wanted to finish the event but there are a lot of positives to take from it."

Thompson also captured the Vare Trophy for the LPGA's lowest scoring average for the season.

"To get my name on the Vare Trophy is a real honor," Thompson said. "Winning the Vare trophy showed that all my hard work in the off season really paid off and I can't wait to do that again this off season."

Thompson picked up four birdies on the front nine, before adding two more at at 13 and 17 before her nightmare closing bogey.

Ariya opened with her lone bogey, bounced back with birdies at four and six and then birdied 13 and 14 before her finishing heroics.

The LPGA Player of the Year award was shared for the first time, with South Koreans Park Sung-Hyun -- also the LPGA Rookie of the Year -- and Ryu So-Yeon being named co-winners.

US Women's Open champion Park matched Nancy Lopez as the only players to win top player and rookie awards in the same year.