* Matthew makes up seven shots in final round (Adds details, quotes)
June 9 (Reuters) - Park Inbee of South Korea won the LPGA Championship in a marathon Sunday finish, winning a three-hole sudden death playoff over Briton Catriona Matthew with a birdie on her 39th hole of play.
It was the 24-year-old Park's second major title of the season following her triumph in the Kraft Nabisco Championship and underlined her status as the women's world number one.
"It was one of the toughest days out there," Park said after sinking an 18-foot birdie putt at the par-four 18th at Locust Hill outside Rochester, New York, to defeat Matthew after they both parred the first two holes of sudden death.
"I'm so tired."
The entire third and fourth rounds were played on Sunday after Thursday's opening round was wiped out by heavy rains and lightning.
Tied for third place on four-under-par 284 were American Morgan Pressel, who shot a final-round 75, and Norway's Suzann Pettersen, who fired a seven-under 65 in the final round, the best score of the tournament.
Park took a one-shot lead over 36-hole leader Pressel into the final round and led by as many as three strokes before losing her way off the tee en route to a 75.
Matthew, 43, made up seven shots on Park in the final round, posting a bogey-free, four-under 68 to take a five-under-par total into the clubhouse and force a playoff after the Korean made three bogeys over the last five holes to tie her on 283.
"I didn't hit many fairways out there and I was scrambling really well out there," said Park. "I think I was actually really lucky to get in the playoff.
"The amount of fairways I was missing it's almost a miracle that I won today. I think I got a little lucky there, too. And I really tried to fight and tried not to give up. That really paid off."
In contrast to the final round, in which Matthew played impeccably and Park struggled finding the fairways, the Korean had the steadier hand in the playoff.
Park, who missed eight fairways in the final round and struggled out of the deep rough, regained her swing off the tee in sudden-death.
On the decisive playoff hole, Park split the fairway, while Matthew landed in the rough behind a large tree right of the fairway.
After the Korean put her approach safely on the green, the Scot punched out through the fairway and into rough short of the green. Her next shot also failed to reach the putting surface and then she chipped up weakly below the hole.
"When I started the last round I probably didn't realize I could win," said Matthew, winner of the 2009 Women's British Open. "So to play well and get into the playoffs was obviously pretty good.
"She's not the kind of player you'd expect to fall back."
After Park rolled in her birdie putt for her third career major and fourth victory of the year, she was doused with water by compatriot Chella Choi, who finished at three-under 285 and joined the celebration as Park extended a streak of nine successive women's majors won by Asian-born players.
(Reporting by Larry Fine in New York; Editing by Gene Cherry)