Lewis holed from 18 feet to secure the 13th LPGA Tour title of her career after finishing tied on five-under par with compatriot Cheyenne Knight, Spain's Azahara Munoz and Denmark's Emily Pedersen.

Munoz and Pedersen were unable to make unlikely birdies from long range and Knight missed her birdie attempt from 15 feet to keep the play-off going.

Lewis, who won the 2013 Women's British Open at St Andrews, began the day a shot behind Munoz but made the ideal start with birdies on the 2nd and 3rd after Munoz had three-putted the opening hole.

Munoz looked to be out of contention as she double bogied the 6th and dropped another shot on the 9th to be out in 40, but Lewis pitched into a bunker on the 11th to make her own double bogey as all the contenders began to struggle.

“I fought really hard. I made some really nice putts coming in and that's all you can do.” – Azahara Munoz

Three birdies in the first seven holes had given American Jennifer Song the lead on eight-under par, but she played her last 10 in five over to miss out on the play-off by two shots.

Pedersen was first to set the clubhouse target after a closing 68 and was soon joined by Knight, with Munoz bravely saving par on the 18th from 10 feet after Lewis had never threatened to hole a long birdie attempt to win in regulation.

Overnight leader Munoz, who carded a final round of 73, said: "I'm proud of myself. Obviously it was a tough day and I didn't have a good start.

"I got pretty unlucky on number six. I got a plugged lie in the bunker so I had to take an unplayable. But I fought really hard. I made some really nice putts coming in and that's all you can do."

Western Australians Hannah Green and Minjee Lee tied for 16th after finishing five shots off the pace.

Lee, who was sitting eighth overnight, shot a two-over par 73 to slip down the leaderboard.

- Phil Casey, PAA