Australian Hannah Green made her first LPGA Tour victory a major when she won the Women's PGA Championship by one stroke from South Korean Park Sung-hyun in Chaska, Minnesota on Sunday.

Green got up-and-down from a greenside bunker at the final hole, sinking a clutch four-foot putt for the victory at Hazeltine National.

She carded an even-par 72 to complete a wire-to-wire triumph.

Green finished at nine-under 279, while last year's champion Park (68) birdied the final hole for second place on 280.

"I was really nervous playing the last five holes," Green said, her voice cracking with emotion.

"To be winning a major as my first event, I'm really over the moon."

The 22-year-old from Perth, Western Australia, came into the championship ranked 114th in the world.

She built a handy lead in the final round before all but frittering it away with three bogeys in a four-hole stretch around the turn.

She steadied the ship after that and a 15-foot birdie at the 16th hole proved decisive.

Park, playing in the group ahead, was not done though. She birdied the par-four 18th to put the heat on Green, who hit a poor six-iron into the sand trap.

However, Green found herself with a good lie and nipped the bunker shot nicely, before sinking the putt, leading to a teary celebration as her boyfriend, compatriot Karrie Webb and several friends rushed onto the green.

American Nelly Korda (71) and England's Mel Reid (66) tied for third, three shots behind.

Thailand's Ariya Jutanugarn, who started the day one shot behind Green, had a nightmare 77 to plunge into a tie for 10th on three-under.