Taupo's Cameron Todd, a former national age-group rep, used his run prowess to kick clear of the men's field, winning in 50:31 - a far cry from last year when he was pipped by Graham O'Grady by two seconds in the closest finish in history.
Nielsen, in her first crack at the Surfbreaker, is only just getting back into competition after a post-Beijing comedown that took some of the gloss off of her golden moment.
As if contracting chicken pox wasn't enough, Nielsen had weeks of feeling lethargic before picking up a hip injury.
"It was all a bit of disaster really. I've still got great memories of becoming world champion, which is the highlight of my career, but the chicken pox, then the tiredness followed by the hip injury was probably my body's way of telling me I'd overdone it and to slow down."
Nielsen is planning a move to up into the ITU Olympic distance, but when is unclear. She has another two years left as an age-grouper in sprint distance and may do another 12 months there while continuing to study through correspondence school.
"Whangamata [next Tuesday] will be my first time doing the whole thing [standard distance] by myself, and as much as I'd like to move up next year I'll probably give it another year where I am."
Todd, 19, is also in a state of flux, with triathlon taking a back seat to the first year of studying towards a commerce degree at Auckland University this year.
Fifth at the world age-group triathlon champs three years ago in Vancouver, and sixth a year later on the Gold Coast, Todd will continue to chip away at the sport when he gets time to lift his head out of the books.
"It's been hard this year to get away and compete with exams, and hard to find the spare time to put in. The next two years is all about studying but if I can I'd love to spend time focusing on my running speed because if you look at the top [Olympic distance] guys they're all doing sub-30mins for 10km and I'm a way off that."
There was nothing wrong with Todd's leg speed yesterday, with his 17:00 split for the 5km the quickest of the day.
The team's race was dominated by two-person team Super Heroes in Training - swimmer Stephanie Capp and cyclist/runner Aiden Dunster - for a 55:09 finish, with the Brick family second as swimmer Claudia handed off to dad and former duathlon world champion Ma, before mum Tracey ran them home to finish in 55:54.
Eves Surfbreaker sprint distance triathlon
(750m swim, 16km bike, 5km run)
Male: 1 Cameron Todd 50:31, 2 Andrew Lloyd 51:21, 3 Owen Miller 52:12, 4 Thomas McLaughlin 52:28, 5 Todd Davidson 53:53.
Female: 1 Mikayla Nielsen 56:14, 2 Samantha Kingsford 58:08, 3 Nicole Van Der Kay 58:21, 4 Suzanne Cheater 59:33, 5 Alice McFall 1:01:11.
UCan2
(375m swim, 8km bike, 2.5km run)
Male: 1 Sam Roy 31:41, 2 Callum Knox 34:57, 3 Grover Brick 42:38.
Female: 1 Amanda Rowe 39:46, 2 Laura Wyatt 41:31, 3 Stefanie Cullen 42:44.