A tight group of four boys emerged from the water for the five laps which made up the 19.3km bike ride, heading up Somme Parade before turning around on Glasgow St.
Mount Aspring College's Janus Staufenberg would leave the group behind at the transition, building up a 5m lead, which he would maintain on the 5km run, consisting of two laps up and down the boardwalk.
Staufenberg would continue to see daylight, winning the race in 53m 8s, but found the hard-charging Bradley Cullen (Hamilton Boys) coming in ten seconds behind him, having overcome issues on the bike to leave behind the chasing bunch and then run down everyone else in the Top 5 except Staufenberg.
James Matthews (Sacred Heart College) hung on to third in 53m 30s.
"As tired as I thought I would be," said Staufenberg, who put in six days a week training.
"That last 500m hurt."
Third coming out of the water, he had worked in concert with the others around him like Matthews, Josiah Ney (Gisborne Boys) and Saxon Morgan (St Andrews), then when they transitioned off the bikes, it was every man for himself.
"Just leading pack for the bike [were] working hard. We could get away from the chase pack."
Cullen was philosophical about getting so close.
"I knew [Staufenberg] was going to be hard to run down.
"Thirty-five seconds on us going into the run and I got it down to 8s in the end. But that's racing.
"I overshot the u-turn [at Glasgow] and couldn't get back on [the lead pack].
"Just an annoying chase group - 4-5 of us but not doing that much."
Making no contest of the Under 19 girls was Hannah Knighton of Waikato Diocesan, who smashed the field in 1h 33s, to finish over two minutes ahead of runnerup Amelia Persson (St Margaret's College) in 1h 2m 46s, while Knighton's schoolmate Emily Irvine was third.
Knighton led out of the water and never looked back.
"That was the plan. Plan A - just go for it," she said.
"Last one of the season so make the most of it."
Although not used to river swimming and finding the branch navigation bemusing, Knighton could hear her coaches calling from the sidelines on Somme Parade and put all her training with the Tauranga Tri-Academy to good use.
The other age grades took on the course in decreasing lengths according to age.
The biggest fields were found in the Under 16's, with Dylan Mccullough (Saint Kentigern College) winning the boys race in 42m 2s, while Olivia Cummings (Otumoetai College) was the girls winner in 47m 26s.
Under 14 winners were William Taylor (CBHS) and Sacha Mcleod (St Kentigern), and in the Under 13's it was Sam Idiens (Christs College) and Sophie Spencer (St Kentigern).
The Under 12 winners were Art Aitken (Medbury) and Manaia Elliott (Cambridge Middle School).
Team triathlon followed yesterday afternoon.
Today's action begins with the aquathon with races starting from 8.30am to 10.20am, followed by Tag Team Triathlon from 12.30pm to 2pm.
