He dug deep and took control of a race held in brutal conditions.
There was no escape on the course from howling northwest winds, which gusted up to more than 50kmh and became the bane of competitors during a race several veteran professionals labelled afterwards as the hardest of their lives.
Whyte's win was all the more impressive given it was only his second professional appearance at the 226km distance, while prolific Australian triathlete Belinda Granger was at the other end of the scale in winning the women's race - her 13th title from 41 events.
Granger's win was her second Challenge Wanaka title and came four years after she won the inaugural race in 2007.
Former farm boy Whyte (29), who was raised near Riverton and studied surveying at the University of Otago, led from start to finish in an event which he needed a "special exemption" to enter.
"My fiancee's sister is getting married today. Fiona wasn't too happy when it clashed with this race, but hopefully she'll understand now I've picked up the win," Whyte said.
Given the race-day conditions, Whyte may have preferred to be relaxing in the genteel surrounds of a family wedding reception at Kinloch, near Taupo, instead of taxing himself to the limit in a torrid battle against the wind.
Pale, drawn, and hunched over on a cot in the first-aid tent after the race, Whyte said the race was a brutal affair.
"It was hard, so hard, out there on the bike. We rocketed down to Cromwell with it behind us, but once you turned it was like hitting a brick wall."
The head wind caused heartbreak for Aucklander Belinda Harper, who had established a six-minute lead over Granger on the bike, before a freak gust caused her to crash on a downhill stretch of highway between Tarras and Luggate.
A bloodied and shaken Harper struggled to repair her bike and was soon overhauled by the Australian veteran, adventure endurance athlete Christie Syms, and Wanaka triathlete Simone Maier.
Whyte and Australian Josh Rix had opened up an early lead on the rest of the men's field during the 180km bike leg, after the pair exited the swim in front.
Recording speeds of more than 60kmh on the cruise to Cromwell, they turned at the halfway mark for the headwind slog up Lake Dunstan back, and saw their bike speed drop back to less than 20kmh.
As Rix started to lag and the pack closed, Whyte said he had to "dig deep" and commit to going out on his own.
"I told myself you can't build that big a gap and let it disappear ... In the end, I couldn't have asked for a better result," he said.
Whyte's efforts into the wind meant he held a five-minute lead by the time he set off on the marathon, and the chasing bunch swapped positions as they tried to close the margin.
The head wind proved too much for Rix and he was overtaken by a group which included Kiwis Bevan McKinnon and Keegan Williams, and a threatening Courtney Ogden, of Australia.
McKinnon led the Whyte chasers, followed by Ogden, then Williams, who kept closing during the first lap of the exposed off-road run course.
Williams passed Ogden at the 18km mark to briefly entertain hopes of a Kiwi podium finish, before the gutsy Australian got a second wind in the second lap.
He surged past a fading Williams and then ran down a tiring McKinnon in the final 2km to claim second behind the unchallenged Whyte, who received a deserved warm welcome from the Wanaka crowd as the second New Zealand champion in the event's history.
Granger never looked back as she settled in to her run, while Maier ran home strongly to really give the home crowd something to cheer when she crossed the line in second place.
