World number one Inbee Park finished in third place at seven-under.
"I didn't know I would do it this quick. I'm just so fortunate to do it at such a great tournament," Ko said at the award presentation.
"I was nervous, but before my day started today I just said concentrate on your game. Like I always say you can't really control what the opposition does'."
Ko announced she was turning professional in October after picking up four pro tournament wins as an amateur, including back-to-back Canadian Open titles and the NZ Open earlier this year.
The world no. six finished in a share of 21st place in her professional debut at the CME Titleholders in Florida last month, earning her first cheque of NZD$20,000.
''Two tournaments, two cheques, I'm pretty happy with that," Ko said.
Guy Wilson, her coach since she was six years old since they met at the Pupuke Golf Club on Auckland's North Shore, was watching the action live in New Zealand and was once again blown away by his young prodigies' composure.
"I am hugely proud of how Lydia has proved she is not a player of the now but a player of the future," he said.
"She is someone that everyone will talk about for a long, long time. It proves we can create world champions here in our country when we have the right ingredients."