He had another scare towards the bottom of the Signal Hill course but the experienced 29-year-old rider stayed upright and got to the finish faster than anyone else.
"I almost threw it away in the first couple of corners," The Norco Factory Team rider said.
"There was another massive moment at the bottom. You just had to get through it."
The cross-country competitors got the best of the Dunedin’s weather on Saturday but rain arrived yesterday and the track got awfully slippery.
Blenkinsop, who is based in Christchurch, was one of six riders who had to restart their run after Queenstown rider Jamie Lyall crashed. A red flag came out and racing was held up for about an hour.
The delay was unsettling and Blenkinsop felt conditions had got worse, despite the rain clearing.
"When it rains, [the track] gets a little bit cleaner. But this run there was no rain, so it clogged up a bit and we were sitting around for a while and you get a few things going through your head."
He took the descent cautiously but still recorded a good time of 3min 13.65sec.
Blenkinsop has consistently been the best of the New Zealander riders for more than a decade but had never won an Oceania title.
"I’ve been close before but to get the win is great. It was also good training in these wet conditions because we can get them in the World Cup season."
Guest rider Guy Gibbs was the next-fastest with a time of 3min 19.82sec and New Plymouth’s Wyn Masters took third place in 3min 29.77sec. Dunedin rider Calum Booth (3min 52.66sec) was off the pace.
West Auckland’s Virginia Armstrong won the elite women’s title from Tauranga’s Shania Rawson.
In the age grades, Sam Robbie (Queenstown) won the under-19 men; Guy Johnston (Thames) the under-17 men and Patrick Duff (Methven) the under-15. The women’s under-17 honours went to Wellington’s Nikki Clarke.
New Zealand cross-country riders Anton Cooper and Samara Sheppard successfully defended their titles on Saturday.
Cooper powered past compatriot Sam Gaze, who had stopped to adjust his seat midway through the race. He pushed on to a dominant victory in 1hr 21min 54sec.
Gaze had to stop for a second time to deal with a mechanical issue and finished two minutes back in second place. Australian Cameron Ivory claimed third.
Sheppard took command on the gruelling climb during the second lap and eventually won the race in a time of 1hr 24min 28sec.
Australian Holly Harris claimed second and former New Zealand national champion, Kate Fluker, was third.
Phoebe Young prevailed in the women’s under-19 race. Auckland’s Charlotte Rayner won the women’s under-23 title.
There was a Nelson double in the women’s age groups with Rebecca Hufflett winning the under-15 title and Zoe Nathan claiming the under-17 honours. Eden Cruise was in outstanding form to win the under-23 men’s title by nearly two minutes.
World champion Australian Cameron Wright was in a class of his own to win the under-19 race.
