HILTON HEAD ISLAND, S.C. — Early on, Satoshi Kodaira was thinking only of playing well enough Sunday to make it to next week's PGA Tour stop.

Those worries are over for the 28-year-old from Japan, who rallied from six shots behind to win the RBC Heritage in a playoff and gain an invitation to join the tour as a regular.

"This is a stage I've been dreaming about," Kodaira said through an interpreter. "And having this opportunity to play full time is a dream come true. So, of course, I will accept full-time membership."

Kodaira defeated Si Woo Kim on the third playoff hole, rolling in a 25-foot birdie on the par-3 17th hole, then punching his fist in celebration. It ended a drama-filled final round in which it appeared that Kim, Ian Poulter and Luke List had the lock on the title at different points.

But it was Kodaira's relentless grind to the top that won the day. And with the game he showed at Harbour Town Golf Links, Kodaira appears like he's got more big moments on tour ahead like countryman and five-time tour winner Hideki Matsuyama.

"I feel like I'm getting closer to that level," said Kodaira, who is ranked 46th in the world and has played in 15 tour events. "I'd like to do my best in major championships and, hopefully, work hard at it."

Bryson DeChambeau (66) and List (72) were tied for third. Third-round leader Poulter's bid for a second tour title in three weeks ended with a 75 and a tie for seventh.

Starting times for the final round were moved up because of a forecast for bad weather.

Kodaira won $1.206 million. He'll be exempt on the PGA Tour through the 2019-20 season.

The tournament appeared in steady hands with Kim, whose bulldog focus and shot-making held everyone off to win The Players Championship last May. But the 22-year-old from South Korea faltered over his final nine holes of regulation, with three bogeys to fall into the tie with Kodaira.

Kim had the chance to win in regulation but missed a six-foot birdie putt on the 18th hole.

"I tried my best and the putts didn't drop," Kim said. "It is what it is."

Poulter, who dramatically won the Houston Open two weeks ago for his first tour win in more than five years, had six bogeys Sunday after making just two in his first three rounds.

Kodaira was the hardest charged and few even realized until the final threesome of Kim, Poulter and List all came back to the pack. Kodaira became the sixth straight RBC Heritage champion who was three strokes down or more at the start of the final round.

Playing Harbour Town for the first time, Kodaira opened with a 73, then followed with the tournament's best round of the week, 63, on Friday. That game kicked in once more in the final round, with six birdies on the way to the playoff.

Dustin Johnson finished with his best round of the week, a 67, and tied for 16th, ensuring that he will stay at No. 1 in the world for at least the next two weeks.

RAHM WINS SPANISH OPEN: Jon Rahm shot a 5-under 67 Sunday to win the Spanish Open with overnight leader Paul Dunne two strokes behind.

The fourth-ranked Rahm had six birdies in his final round to end the Centro Nacional de Golf tournament on 20-under 268.

The 23-year-old Spaniard earned his third European Tour win a week after finishing fourth at the Masters in Augusta.

"When I made the decision to come straight from Augusta it wouldn't be to just show up and walk around, I wanted to win this tournament," Rahm said.

It was Rahm's first professional win at home.

Dunne (71) entered the final round with a 1-shot lead over Nacho Elvira (71) but three bogeys ruined his chances of a second tour win.

Elvira finished third at three shots behind Rahm. George Coetzee was a shot further back in fourth after a 63.

HENDERSON WINS IN HAWAII: Brooke Henderson pulled away Saturday at gusty Ko Olina Golf Club to win the Lotte Championship for her sixth LPGA Tour victory.

The 20-year-old Canadian closed with a 3-under 69 for a four-stroke victory. She moved within two victories tying Sandra Post's LPGA Tour record for Canadians.

A stroke ahead entering the round after late putting trouble in a third-round 73, Henderson finished at 12-under 276.

Spain's Azahara Munoz had a 67, the low round of the day, to finish second.

Top-ranked Shanshan Feng (71), third-ranked Inbee Park (72) and sixth-ranked Ariya Jutanugarn (69) tied for third at 7 under.

With rain squalls and wind gusting to 30 mph, Munoz and Jutanugarn put together the only serious charges of the final round. Both came up a few holes short.