"I don't think I've ever dug that deep before. I hit the wall at 10km to go. It was painful."
The unique conditions in Kona will present Docherty with new challenges - the heat and wind on the cycle and run legs sap the energy of even the best athletes and the field is always high quality.
Brown, who before Saturday was unbeaten over the full distance at Taupo, has never won at Kona, although he has been second twice, in 2001 and 2005 and was third in 2002 and 2003. Last year he didn't make the start line due to an allergic reaction to volcanic gases and a year earlier failed to finish.
While time is running out for 40-year-old Brown, Docherty's stunning debut and fast legs from his days racing the Olympic distance ITU circuit suggest there could be a changing of the guard.
"I've still got many years left in my career," said Docherty, who turns 36 this month. "The ultimate goal is to do well in Hawaii. I've still got a lot of work to do but it's certainly a good start to my long-distance career."
Kellogg's Nutri-Grain Ironman New Zealand results (3.8km swim 180km bike 42.2km run)
Elite men: Bevan Docherty (NZL) 8:15:35, 1; Marko Albert (Estonia) 8:25:30, 2; Cameron Brown (NZL) 8:34:28, 3.
Elite women: Meredith Kessler (USA) 9:17:10, 1; Gina Crawford (NZL) 9:20:54, 2; Candice Hammond (NZL) 9:35:52, 3.