Since winning her first professional event in Australia at the age of 14, Ko's extraordinary talent has never been in doubt and in February she became the youngest world number one in just her second full season as a professional.
But the clamour to validate herself with a major has been a heavy weight on the teenager's shoulders, and tears welled in her eyes as she approached her final hole with an unassailable five-stroke lead on Sunday.
"I kind of got a little overwhelmed," Ko told reporters after a flawless final round of 63 left American Lexi Thompson a distant second.
"I thought back over the whole week, all the questions that have been asked, so in a way I was relieved.
"Winning at any age is amazing at a major. All players want to peak at the their best at a major. To say that I'm the youngest in history for now is so cool.
"The big thing for me is that I won't be asked that (major) question again."
The only question left for Ko, who was 18 years, four months and 20 days old when she lifted the trophy on Sunday, is how many more she can win.
Ko will be mindful that American Morgan Pressel, who she eclipsed as the youngest major winner, made a similar splash when she won the 2007 Kraft Nabisco Championship at the age of 18 years and 313 days.
Pressel has won just one LPGA event in the eight years since.
Ko's coach David Leadbetter believes the Seoul-born prodigy is now primed to dominate the game like few others.
"At the age of 18 it's incredible what she's done, and the potential for the future," he told New Zealand radio.
"The floodgates will really open now that she's won her first major and got that so-called monkey off her back.
"The confidence is now there, she's really ready now to take the game by the scruff of the neck."
Ko became only the third New Zealander to win a major, with Michael Campbell and Bob Charles winning one each on the men's tour.
She can expect a hero's reception when she returns to Auckland, where local media have called for a ticker-tape parade.
(Story corrects Ko's age)
(Editing by Peter Rutherford)
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