'I really put it together this week and learned a lot from my past experience,' said Nirapathpongporn. 'I think this is the top of the amateur level. In college, I am the national champion, individually and team, and I won the Honda Award and that's about as high as you can get in college.'
Nirapathpongporn had an early 1-up lead, but lost three consecutive holes from the par-5 sixth to fall 2-down.
Park, playing in her first Women's Amateur, was unable to maintain that advantage. Nirapathpongporn rallied with wins at the ninth and 14th to square the match.
Nirapathpongporn used the win at the 14th to pick up momentum. She won the 15th to regain the advantage in the match and won the next two holes to go 3-up through 17 holes.
Park two-putted for par on the 18th while Nirapathpongporn stumbled to a bogey. Nirapathpongporn took a 2-up lead into the afternoon 18.
'I think it played a little bit more difficult this morning because it was wetter,' Nirapathpongporn said. 'It was difficult this morning, playing on wet fairways because you are thinking chunk or thin, it's just hard to go at it.'
As the second portion of the match began, Nirapathpongporn moved her advantage back to 3-up with a win at the par-4 first. Park came back to birdie the par-5 third to get back to 2-down.
Nirapathpongporn's lead dipped to a 1-up advantage when she bogeyed the par-4 fourth. Park continued her surge with a birdie at the next to briefly square the match.
The Duke standout responded quickly though. She won the next, the 24th hole of the match, to regain a 1-up lead. The duo went on to par the next five holes as Nirapathpongporn took a 1-up lead to the par-5 30th hole.
Nirapathpongporn rolled home a birdie putt to extend her lead to 2-up. Park came right back to birdie the next and get back to 1-down.
'I think the biggest high point today was that putt on No. 13, where I made that 20- or 25-footer,' Park said. 'I got to within 1-up, but I guess the momentum was just on her side today. I just didn't pull it off the way I'd like to.'
Park three-putted on the 32nd hole to drop back to 2-down with four holes to play. The pair parred the following two holes.
Nirapathpongporn sealed the match at the 35th. Her second shot found the green while Park's second came up short. After Park ran her chip past the hole, Nirapathpongporn lagged her birdie try within a foot of the cup. That putt and the match were conceded.
'All day long, especially the back nine I kept knocking it close,' said Nirapathpongporn. 'Sometimes I had difficult shots but I said the reason why I am the best player is because I keep hitting those shots. I go right at the pin because I know I can, I am not going to stay conservative and let other people take the hole.'
Park did not come to the event with high expectations, but wanted to better her game.
'I just came here to have fun and learn more and get better at this game,' said Park. 'Golf is not perfect. You can never perfect it. I think I played very well this past week. I think I played very well the past couple of days but not today, but it's okay.'
Nirapathpongporn moved to the United States at the age of 15 to learn the game of golf. Ever since moving here, she has lived on her own.
'I am just so proud of myself of how I have grown up the last six years, but I know my parents are there in Thailand but they are very far away,' she said. 'They can be my guidance, they can give me emotional support, and give advice and all that, but I am the one executing, making the decisions and just the way I have grown up the last six years, I am just so proud.'
She had plenty of praise for her opponent as well.
'She never lost it. She stayed right there,' said the 21-year-old Nirapathpongporn. 'She seemed a little tight at the very first hole of the second match. In the morning she was smiley, then she seemed all business in the afternoon, but she really held it together.'