Now Longopoa is leaving others in his wake, having run in First XV hat-tricks against Auckland Grammar and Otahuhu. He is also the back-up goalkicker. As a left-footer, he has received some good tuition in that area from Suburbs premier captain and No 10 Carl Perry.
Longopoa says "everything clicked" in the extraordinary 50-0 win over Auckland Grammar. Coming back down to ground and refocusing was important. He did that to good effect in last Saturday's 53-3 victory over Dilworth, in which he scored a nice solo try and was awarded player of the day.
Longopoa's athletics helps his rugby, and vice versa.
"Rugby helps with my fitness for athletics and athletics helps my rugby for speed and endurance. I used to be a bit too big for athletics and a bit too small for rugby, so I had to try and balance that out," says the Auckland Under 18 rep. Now he is 85kg and happy around that weight.
He has enjoyed success in the hurdles and long jump at Auckland, North Island and national schools level, though last year there was a clash with the schools nationals and the Condors 7s. The latter won out.
This year there is again a clash, but the schools nationals are at Mt Smart and Condors at Sacred Heart, so he has a plan to possibly do both.
Family support is strong, and his younger sister Kalisi is already showing real promise as a hurdler.
Longopoa is keen to play his club rugby next year at Grammar TEC, while he is eyeing up some form of tertiary study. Longer-term, rugby will probably win out over athletics, as he enjoys the team environment.
"Niven is a great example of what a young sportsman at MAGS can grow into," says First XV coach Geoff Moon. "He trains independently, does extras, and all the young ones can see that. He's lifted standards and he's got a magnificent temperament."