'What a day it was,' said Park, who earned $240,000 for the win. 'Nobody said it was going to be easy and it wasn't. But I pulled it off and I am very thankful. It's something very special to have my name as the first winner of the Michelob Light Open.'
Karrie Webb fired a 4-under 67 in the final round to get to 8-under-par 276 and share second place with Lorena Ochoa (69) and Cristie Kerr (71).
Park, who led Kerr by one heading into the final round, fell well back after a double bogey at the first and a bogey at the second. Her slide continued with another bogey at the fourth.
'I putted well even though I missed the putts on 1 and 2,' said Park. 'I stroked it well so I knew that wasn't it. The swing comes and goes. I knew that if I made a couple of practice swings it could come back.'
She found the form that got her the third-round lead after that. Park rolled in a birdie putt at the par-3 fifth and followed that with birdies at Nos. 6 and 7 as she made the turn at 1-over for her round.
'I kept looking at the leaderboard to see where everybody else was,' Park said. 'I knew if I could just keep making pars and a few birdies, I would have a chance to pull it off.'
On the back side, Park dropped another shot at the par-4 10th. She atoned for that mistake with back-to-back birdies from the 15th to reclaim the lead.
Park was able to get up-and-down for par on each of the final two holes to secure the victory.
'The putt on 18 was kind of a double-breaker,' Park said. 'My caddie helped me line it up and we just kept playing around until the line felt right.'
Kerr grabbed the lead at minus-10 with an eagle at the par-5 seventh. However she dropped a shot with a bogey at the ninth.
Around the turn, Kerr got back to 10-under with a birdie at the par-4 14th. She stumbled again at the next with a bogey, but still held a one-shot lead.
Kerr missed the 16th green and was unable to get-up-and-down for par. After she bogeyed, Park rolled in a birdie putt to re-take the lead. Kerr was only able to manage par on the final two holes to lose by one.
'Coming down the stretch, I hit two shots which cost me two bogeys,' said Kerr. 'I felt really good out there, the way I was striking the ball. You know it just happened at the wrong time.'
Kerr, who is still searching for her first victory of 2003, was eager to get back on the course.
'I'm anxious right now. Let's go tee it up,' said Kerr. 'I feel like I'm getting real close to winning. I'm getting a little antsy.'
Webb started her round with a pair of birdies over her first nine holes. Around the turn, she dropped a stroke at the par-4 12th but the Australian climbed into a share of second with three straight birdies from the 13th.
Ochoa got into contention with a strong front nine. She birdied the third and fourth to get to minus-8. She briefly moved to 9-under with a birdie at the par-5 seventh but Ochoa faltered with a bogey at the next. The Mexican managed just 10 pars the remainder of her round to share second place.
Mi Hyun Kim finished alone in fifth place at 7-under-par 277. Annika Sorenstam, whose next scheduled event in America is on the PGA Tour at the Colonial, was one stroke back at minus-6. Jenny Rosales came in seventh alone at 5-under-par 279.