Kim hit a 7-iron that stopped 2 feet behind the hole for a birdie to claim the eighth and final spot in the final round, giving her just as much of a chance as anyone to win the $1 million prize.
With a bleacher full of sun-baked fans still cheering, Kim charged over to caddie Donna Southam and leaped with a twist, slightly higher than when Phil Mickelson won his first Masters, and they bumped each other to celebrate the clutch moment.
It got even better when Nicole Castrale hit her approach into the water, just as she did in regulation, to fall into the playoff.
So concluded another nerve-racking afternoon at Trump International, where eight of the 16 players who qualified for the 18-hole shootout on Sunday had every reason to dream of the biggest payoff in women's golf.
Lorena Ochoa was solid as ever, playing bogey-free for a 6-under 66 to tie for the low round Saturday with Paula Creamer, who was helped by a wedge she holed out for eagle on the par-5 15th.
Karrie Webb, whose 50-foot birdie putt Friday enabled her to avoid a playoff, had no stress in her round of 68. The other qualifiers were U.S. Women's Open champion Cristie Kerr, Natalie Gulbis, Sarah Lee and Mi Hyun Kim, who had the best turnaround of all.
Mi Hyun Kim was at 5 under with five holes to play and still in good shape after bogeys at the 14th and 16th. But she caught a plugged lie in the bunker on the 18th that led to double bogey, and minutes later, she was in a 4-for-2 playoff starting on the 17th tee.
One swing changed everything.
Kim hit a hybrid 5-iron to 7 feet for birdie to earn a spot in the final round.
'I feel so sad after that,' she said of her double bogey. 'Anyway, I made it. Scores are zero tomorrow.'
Just like the third round, the scores will be wiped out for the final 18 holes, where the winner gets $1 million and second place gets $100,000, the biggest disparity of prize money in golf.
'It's all-or-nothing,' Creamer said.
But there were plenty of players who felt like nothing when they left Trump International.
Sophie Gustafson endured a roller-coaster round in which she followed two bogeys by driving the par-4 sixth green and chipping in for eagle, running off four straight birdies to get safe, they finishing double bogey-bogey to fall into the playoff at 1-under 71.
Her tee shot went through the green and into the stream to the left, and she was out.
Juli Inkster never even got that chance. She was on top of her game for the front nine, when she went out in 32. But a three-putt bogey on the 13th started her fall. She took bogey on the 16th, then hit into the water with a 7-iron and made double bogey and finished one shot out of the playoff.
Morgan Pressel made three bogeys in a four-hole stretch on the back nine and also missed out.
The emotions started to wear on the players as the $1 million prize got closer.
Castrale was at 2 under until she hit into the water on the 18th and did well to get up-and-down for bogey. As she fought back tears, she learned that Gustafson had made bogey on the 18th with a fat bunker shot, meaning there would be a playoff.
'I've still got a chance,' she said.
But it lasted only two holes, with Christina Kim hitting a clutch shot and delivering a celebration rarely seen in golf.