Grace Park finished alone in second place at 22-under-par 266 while overnight leader Annika Sorenstam was three shots further back at 19-under-par 269. Sorenstam was joined by Hee-Won Han and Patricia Meunier-Lebouc in a tie for third.
Pak was on fire early on the Championship Course at Moon Valley Country Club and grabbed a three-shot edge around the turn thanks to a remarkable front nine that featured two eagles. However, the defining moment came on the penultimate hole when her competitors had battled back and Pak seemed to be in trouble.
She hit her tee shot in the water at the par-4 17th and eventually found herself on the green with a 30-foot putt to save par. Pak calmly drained the putt to maintain a one-shot advantage.
'I think that's the longest putt I got today,' said Pak. 'I had a perfect break and a perfect speed, but I wasn't expecting to make the putt there. It just made my day from that putt. That was the best putt of the week.'
At the closing hole, Pak's approach shot landed within a foot of the cup and she tapped in for birdie to secure her first title of 2003.
'Hole by hole, just go out there, just do my best every shot, every single shot,' said Pak, who pocketed $150,000 for the win. 'But at the same time, I played really aggressive. That helped a lot today.'
Pak was three shots behind Sorenstam to start the final round and stormed out of the gate with birdies on the first two holes. At the par-5 fourth, Pak blasted a 4-iron to tap-in range for an eagle. She bogeyed the sixth but responded at the par-5 eighth with her second eagle of the day.
The 25-year-old birdied the ninth and picked up three birdies and a bogey on the back side for the win.
Park had two birdies over her first nine holes but caught fire on the back half. She two-putted for birdie at the 10th and hit a 7-iron to five feet for a birdie at the 11th.
She birdied the 13th and 15th and hit her second shot to three feet at the par-4 last. Park converted the putt for a round of 65.
'I'm very happy, but I'm bummed at the same time,' said Park. 'Obviously I played four solid rounds, especially on the back side today.'
Sorenstam brought a two-shot lead over Meunier-Lebouc into the final round but the top player in the world could not hold her advantage. She parred her first nine holes before a birdie at the 10th, her only birdie of the day.
'I think I played well,' said Sorenstam, who carded a final-round 71. 'It was one of those days I just had a lot of lip-outs. That's golf. If you play golf long enough you know these things happen.'
LPGA Tour rookie Lorena Ochoa shot a 6-under 66 to finish alone in sixth at 17-under-par 271. Beth Daniel was one shot further back at 16-under-par 272.
Dorothy Delasin finished alone in eighth at 15-under-par 273. She was followed by Michele Redman and Cristie Kerr at 14-under-par 274.
Laura Davies, a four-time winner of this event, was joined by Mi Hyun Kim, Kelly Robbins and Stacy Prammanasudh at 13-under-par 275.