The South Korean captured her third major title, and her first in six years, after ending on five-under-par at Maryland's Congressional Country Club.

Twenty-seven-year-old Chun was superb on day one and led by five shots after a record-equalling round of 64.

She then extended that advantage to six shots after day two, but was pegged back to lead by just three after the third day.

It looked like she might throw away the title entirely on day four today as she dropped four shots on the front nine.

Her three-over round of 75 included five bogeys and two birdies, with American Lexi Thompson looking best placed to capitalise.

However, the one-time major champion bogeyed two of the last three holes to finish a shot behind Chun.

She missed a 15 foot putt for birdie on the 18th which would have drawn her level.

Min-Jee Lee of Australia carded a three-under final round of 70 to rise up the standings and also grab a share of second place with Thompson.

Atthaya Thitikul of Thailand finished two shots off the lead. 

"It just means a lot because I didn't have any wins for almost three-and-a-half years," said Chun, who won the US Women's Open in 2015 and the Evian Championship a year later.

"I want to tell truth, I think I couldn't control all my pressure. 

"That's why I had four bogeys. 

"Then, at the same time, you know, the course is never easy here.

"Sometimes my golf is not perfect so that's what happened on the front nine.

"First nine holes I got a lot of pressure, to be honest, I couldn't enjoy to play golf. 

"I believe if I stick to my game plan and then I believe I have a chance in the back nine, so I try to hang in there. 

"I'm so happy I made it."