Inbee Park claimed her fifth title of the season when she beat So Yeon Ryu in the first play-off hole after both players ended the Walmart NW Arkansas Championship on 12-under par.
The South Korean carded a final round 67 after making a birdie on the final hole, while Ruy - playing two groups behind the world number one - also made birdie on the par-five 18th to join Park on 201 after the third and final round.
On the first play-off hole - once again the 18th - Ruy landed her tee shot in the rough and was forced to lay up short of the green on her approach.
Park made the green in regulation and made an easy birdie putt, while Ruy was forced to try and chip in from the fringe of the green after overshooting her approach.
Her chip shot nearly found the cup, but rolled agonizingly past it to hand Park the victory.
"I've had playoffs the last couple weeks. It was really tough," Park said afterwards.
"It was tough playing with a really good friend in the playoff. It just felt weird.
"I am human. My emotions did not show but I was really nervous.
"It's never getting easier."
The 24-year-old has been in dominant form so far this year, winning both of the majors to take place so far.
"Everything has been going really well," Park continued.
"I've been hitting the ball really good and putting amazing. Everything in my game is really coming together."
In third place, one shot behind the top pair was Mika Miyazato, who led the event after the first round.
Another shot further behind on 10-under par were University of Arkansas graduate Stacy Lewis (71), amateur Lydia Ko (68) and I.K. Kim (69).
golf365.com