Thorburn (29), a public health doctor, won the Otago 10,000m title in 31min 22.67sec in his first race on the track, over 25 laps at the Caledonian Ground.
Clubmate Will Smith was second in 33min 30.93sec and Jason Palmer (Leith) third in 34min 44.58sec.
Thorburn suffered from painful stitch halfway through the race.
"I slowed down and relaxed and it came right in three laps," Thorburn said.
It did not matter in the context of the race, because he won by a massive 2min 8sec from Smith.
Thorburn has been busy with his work and studying for his master's degree, and has not been able to do sufficient training.
He paid the penalty when he was violently sick at the end of the race.
"I've only had six weeks' training and have not done any lactic tolerance work to get ready for a fast finish," Thorburn said,It was only Thorburn's second Otago senior title. He also won the Otago cross-country in July.
It completed a good year for the Dunedin doctor, who also finished third in the 12km race at the New Zealand cross-country in Wellington. His next target is the New Zealand marathon in Rotorua in April and this should be easy for Thorburn, a converted duathlete who switched to running nine years ago when he joined Lin Rayner's squad.
He competed in duathlons in his home town of Christchurch before entering medicine and was third in the two-day event at last year's Coast to Coast. He has also represented New Zealand at the world mountain running championships, and has the endurance to succeed in the marathon.
Smith (28), a Dunedin chemist, was also running in a track 10,000m for the first time.
Shireen Crumpton (Hill City) won the Otago women's 10,000m title for the 10th time in 36min 32.95sec.
Her mother, Myrtle Rough (70), broke her fifth New Zealand masters record for the season when she finished third in the women's race in 49min 57.33sec. Rough also holds the New Zealand women's aged 70 records for the 800m, 1500m, 3000m and 5000m. They have all been set this season.
Sue Cuthbert (Leith) won the title in 41min 58.74sec from Maria Sleeman (Caversham) 42min 34.12sec.
Mark O'Donnell (Leith) won the masters men's title in 37min 2.17sec from clubmate Richard Hendry 37min 30.11sec.
New Zealand champion John Gilmour (Hill City) won the men's aged 17 to 19 decathlon with 5000 points. This included personal best performances in the 400m (53.78sec), discus (25.36m) and 1500m (5min 37.10sec). His best points tally was in the 100m, with 789 points.
Visiting German exchange student Davina Hamann (Hill City) won the women's aged 15 and 16 heptathlon with a personal best points score of 4000. She had personal best performances in the shot put (9.53m) and 200m (27.73sec).
Her teacher at Otago Girls' High School, Jarrod Adams (Hill City), won his fourth Otago senior men's title with a score of 3826 points.
Biddy Skerten (Taieri) won the junior women's aged 17 to 19 heptathlon with a score of 3575 points. This included personal best performances in the high jump (1.38m), long jump (4.91m) and 800m (2min 22sec).
Rosie Robinson (Hill City) won the senior women's 10km road walk in 52min 23sec and Daniel Lord (South Canterbury) the senior men's event in 52min 17sec.
Highlights of other events on the Athletics Otago programme were: Marshall Hall (Taieri) winning the men's discus (50.36m), Matthew Aitken (Hill City) the men's aged 17 to 19 AWD discus (24.18m), Nicole Bradley (Caversham) the junior women's discus with a personal best throw of 36.11, Brent Cheshire (Ariki) the men's high jump with a personal best 1.90m.
