The 20-year-old preserved the five-shot buffer she held when play resumed at Windross Farm at 8.30am Monday to finish at 17 under, ahead of China's Jing Yan at 12 under and South Korean Hee Young Park at 11 under.
American Jenna Song finished alone in fourth at 10 under while Victorian Su Oh was the standout Australian performer, recording her second top-five for the season, finishing in tie for 5th at 9 under.
Henderson began her Monday with a bogey at the par-four 8th, but so too did her playing partners, Spain's Belen Mozo and American Brittany Lincicome.
The Canadian added two more birdies to her final round at the par-three 13th and par-five closing hole to sign for an impressive 3-under 69 in extremely difficult Sunday and Monday conditions and seal her second LPGA Tour title for the season and fifth of her short career.
“This is so amazing to get my first win outside of North America, my fifth win on the LPGA Tour, it is incredible. It is a dream come true and to do it in New Zealand – I am really excited to be here,” Henderson said.
“Brittany (her sister and caddy) and I did an extremely awesome job of adapting to those conditions. All day yesterday I was trying to overcome that one shot deficit in case the tournament got cut short. That drive and that push to keep making birdies is what got me in this position.
“Normally this type of golf course doesn’t suit my game but it now gives me a lot of confidence going forward with the British Open and things like that knowing that I can play well on Links golf courses and especially in terrible conditions like the last two days.
“I played awesome to shoot 69. I hit a lot of good shots. I knew I had a significant lead with four holes to go and tried not to make any major mistakes. But the shot into 17 sealed it.”
Mozo, the leader after three rounds, faltered badly in search of her maiden LPGA title, carding a final round 78 to drop to a share of fifth place at 9-under.
Local favourite Lydia Ko during Monday play.
Home town favourite Lydia Ko briefly pulled into contention when she eagled the par-four 15th by holing her approach, however the former world No. 1 doubled bogeyed the 17th and then triple bogeyed the 18th to drop five shots over the last two holes.
“I played really solid pretty much apart from the last two holes,” a philosophical Ko said. “It was a tough finish but overall my game was solid and there were a lot of positives coming from two good finishes to give me the confidence coming into this week.
“I had hoped a few more putts would have dropped but I think I am saying that almost every week. There’s always something left to improve.
“But overall the crowds here this week were really the cool aspect for me I don’t get to come home very often – but it gave me goosebumps and made me proud to play this event and have it as a LPGA event.”
The leading amateur was New Zealand-based Korean Ayean Cho who was tied for 17th on six-under par.
THE HENDERSON SISTERS: BROOKE & BRITTANY
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