Victory for Rawlence (28), a Dunedin-based research scientist, was set up by his decision to ride a cyclocross bike due to the muddy nature of the course. It allowed him to get better traction and power away from the 170-strong field.
Rawlence said he was able to get a ''real good'' start and build a good lead going into the first hill.
He knew the last two hills were going to be hard, so held something in reserve.
The tactic paid off, and he was able to keep good distance between himself and pre-race favourites Shaun Portegys (Alexandra) and Jason Low (Dunedin), before breaking the tape in 2hr 19min 14sec, with Portegys getting the jump on Low on the last hill to come home second in 2hr 21min 1sec, 1min 22sec ahead of Low.
''It's pretty cool to beat all the mountain bikers actually. That was the goal,'' Rawlence, who came eighth last year, said.
There was further reward for Rawlence when his wife, Anja McDonald, held off a late challenge from Dunedin's Mary Gray to win the open women's title in 2hr 36min 46sec. Gray finished second in 2hr 37min 27sec, while Erin Greene (Queenstown) was third in 2hr 43min 49sec.
Rawlence and McDonald will now prepare for the world single-speed world championships in Alaska in mid-July, and a week later the single-track 6 Challenge in Canada. The 23km short course mountain bike section was convincingly won by Southland junior champion Alistair Green (18) in 1hr 21min 57sec.
It was Green's fifth time on the course, and after finishing runner-up last year he was determined to go one better and claim the short-course title.
Second home in the open men's category of the sort course mountain bike was Dunedin's Ryan Keogh in 1hr 24min 30sec, with John Benny (Kurow) third in 1hr 26min 51sec.
Phoebe Young (13), a year 9 pupil at Mount Aspiring College, won the open women's short course mountain bike section in 1hr 32min 53sec.
