The Thai blew a seven-stroke lead on the back nine to finish her final round at one-over and 11-under par overall, tied with South Korea's Hyo Joo Kim.
She led the field in driving accuracy, hitting 91.7 percent of the fairways and missing only one on Sunday, and was second in total putts, using only 25 in the final 18 holes and averaging 26.63 for the 72 holes of regulation. She birdied the first extra hole, No. 14, while Jutanugarn made a par.
For Jutanugarn, the bogey at the par-5 17th was uglier than the mess she made on the 10th.
It took four playoff holes for Jutanugarn, known as "May", to finally shake Hyo-Joo Kim, a former major victor who hadn't played like one lately until Shoal Creek.
It was a long, sweaty day at Shoal Creek, especially for those who had to complete their second round on Saturday morning before playing the third.
Her day unravelled coming in on the front nine, Ko dropping four more shots, including a five on her last hole of the day to finally fall below the projected cut line.
DeChambeau wasn't even sure where he was when he finished because so many players worked their way up and down the leader board over the final two hours. "Obviously that wasn't going to happen because I was thinking about the outcome too much". I think I rushed putting them in. "So we had a really good lesson before Kingsmill (two weeks ago) and then I actually missed the cut but felt like I played really well". She'd go on to win the CME.
Oh Su-hyun (68) sits at 6 under, alongside Ariya Jutanugarn, who was 1 under through eight holes in her second round. She led the ANA Inspiration of 2016 by two with three to play and slipped to an unwanted treble of bogeys.
Thailand's Jutanugarn-who had sat in the top two all week long, but then lost a 7-shot lead on Sunday -had a chance to win the Open outright on her final shot, but instead missed the seemingly-easy putt and found herself in a two-hole aggregate playoff with Kim. Then I actually put a Callaway 3-wood in last week which has been really good.
Michelle Wie is among eight players tied for fourth, seven shots off the lead. "Not because I want them to play golf, but because I want them to have a good life".
"I've kind of been playing a little bit better since San Francisco so it's just been like gradually a little bit getting better", said Oh who finished 4th at her last start in MI.