"It was fun there at the end, because Jennifer was making putts and I don't think she realized what she was doing," said Stacy Lewis, her playing partner. "I told her when I hugged her, 'I think you just won yourself a golf tournament.' And she's kind of like, 'What?' It was really cute."
Johnson's game was better than cute.
The 21-year-old Californian closed with her second straight 7-under 65 for a tournament-record 21-under 267 total on The Crossings course at the Robert Trent Jones Golf Trail's Magnolia Grove complex.
She birdied four of the final six holes for a one-stroke victory over Jessica Korda and Pornanong Phatlum.
A 15-foot birdie putt on the 17th hole secured the win, and not long after Lewis passed the torch from her 2012 victory.
"Before I hit my birdie putt on 17, I saw that Pornanong was tied with me at 20 and I didn't want a playoff so I was like, 'I'm going to make this thing,'" Johnson said.
The former Arizona State star two-putted for par on the final hole, tipped her cap and headed toward the practice range to hit a few balls in case of a playoff.
But Phatlum was already done and the lead was safe even with Korda's closing birdie. Phatlum, a 23-year-old from Thailand, closed with a 63. Her previous best finish was third at the Kia Classic.
Johnson had only one previous top-10 finish, an eighth-place tie at the 2011 Navistar LPGA Classic in Prattville, Ala. This time she got a win along with a hug and a "Good job, champ" from her father, Mike.
"I'm a little shocked," Johnson said. "I didn't even realize I shot 65. The whole back nine, I don't know what was happening.
"The birdie putt on 17, that's when I started thinking a little more about winning the tournament.
She went home after missing her second cut of the year at the Kingsmill Championship and switched to what she calls her "spaceship putter" because of its appearance. Johnson aid that part of her game had been her Achilles heel.
"I hit the ball really well. It was like when I missed the cut I felt like I should be playing," she said. "And I went and saw my coach right away in Florida and worked some things out, I put the spaceship putter in the bag and now the putts are going in."
Johnson made the winning point in the 2010 Curtis Cup and was 3-0-1. She improved 19 strokes from her 45th-place tie in Mobile last year.
Between this win and Prattville, she's thinking maybe the cuisine deserves some credit.
"I think the barbecue has something to do with it because I'm a real foodie and like when I eat good, I'm happy," Johnson said. "And in both these locations I've been eating barbecue and good tea and pudding and that has a lot to do with my mindset more than I think."
Phatlum three-putted the opening hole for bogey for the third straight day, but rebounded nicely.
"I just concentrate on my game and do what I have to do and try my best," Phatlum said. "Putting very good today, so like I just didn't have pressure on myself."
Korda finished with a 68 that included three bogeys and seven birdies.
Five players finished two strokes back, including Hall of Famer Karrie Webb and third-round leader Chella Choi, a South Korean who was seeking her first win. Swede Anna Nordqvist followed up a course-record 61 with a 69. South Korea's Jiyai Shin shot a 63 and birdied the final three holes, while Thailand's Ariya Jutanugarn had a 65 to join the group at 19 under.