Ryu's 69s give her a six-under 138 total atop the leaderboard with former Women's PGA Championship victor Henderson, who had a 71, and Park, who posted a 72.
Hataoka was looking to become the second Japanese to capture a major since Hisako Higuchi won the Women's PGA Championship in 1977, the only time a Japanese player has won a major in either the men's or women's Tour.
The Smiths Falls, Ont. native showed some frustration on the 11th hole of Kemper Lakes Golf Club, breaking her club after missing a wedge shot, on her way to finishing tied for sixth at the Women's PGA Championship.
South Korea's Park Sung-hyun won the KPMG Women's PGA Championship following the first three-way play-off in the tournament's 63-year history.
Park claimed the championship at Kemper Lakes Golf Course in IL on Sunday after beating her compatriot Ryu So-yeon and Japanese teenager Nasa Hataoka in a playoff.
During the final round, Park had a big save on the par-4 16th hole after she hit her second shot into the water hazard.
Park started the final round trailing Ryu by four strokes at seven-under, and didn't make a bogey over 20 holes on Sunday.
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The Russian kept her cool, however, to hold serve and then break Wozniacki, winning 6-4 1-6 7-5. Caroline Wozniacki battles flying ants during her Wimbledon loss. "From my end I'm very happy".
Park shot a bogey-free 69, while Ryu shot a 73 with plenty of ups and downs. "That's what really made me cry", Park told reporters.
Park secured her second major since her victory in the U.S. Women's Open in July 2017.
Nine strokes behind Ryu entering the day, Hataoka almost pulled off one of the biggest comebacks in LPGA Tour history.
It moved Ryu to 11 under overall, as the 28-year-old looks to add the KPMG title to previous wins at the US Open and ANA Inspiration. Brooke Henderson (74) - second through three rounds - was 5 under. But a birdie on 18 gave her a strong finish despite the heat. She hit a ideal flop to 3-feet and saved par. Her approach on hole 16, when she was one back of the lead, was inches from going into the water.
Nasa Hataoka, who fired a 64 to come from nine shots back to get into the playoff, missed her birdie attempt and was eliminated.
Park saved par on the 16th, then made two more pars to force a playoff with Hataoka and Ryu after all three finished at 10-under for the tournament. "But on the other hand, I haven't won a major yet, so I felt like I had nothing to lose".
After taking a penalty stroke, Ryu put her third shot to the fringe well behind the pin and two-putted from there for her second double bogey of the round. The heavily favored Team Republic of Korea will feature Inbee Park, Sung Hyun Park, So Yeon Ryu and In-Kyung Kim, who finished in a tie for 8th on Sunday to jump past Hye Jin Choi for the fourth spot on the team.