The victory gave Crombie (27), an environmental scientist for Solid Energy, the prestigious national cross-country-road title double.
The tactical slow start to the women's title race might have given Crombie an opportunity to settle into her work, but it was the dogged determination of Otago champion Rachel Kingsford that she found hard to shake over the final stages.
"She was tough. She stuck in there," Crombie said of the threat posed by Kingsford throughout the race.
Crombie was aware of the danger posed by Kingsford, the North Island cross-country champion, who had been below par in the national cross-country because of the flu.
"It was good for her to even turn out really," Crombie said of Kingsford's race at the national cross-country.
"I think that is one of the biggest things that people don't do is push it when they're sick."
Crombie really enjoyed the 10km Butts Rd course and found the laps ideal in length.
"It's good to have the constant support around the course."
This support was evident when the pace went on around the three-quarter stage as Crombie and Kingsford shook off the challenges of Kellie Palmer (Canterbury), Gabrielle ORourke (Wellington) and Kirsty Morris (Otago).
It was only over the final kilometre that Crombie was able to edge away from Kingsford, crossing to finish in 35min 27.75sec, with Kingsford second in 35min 46.56sec and Palmer third in 36min 19.61sec.
The title was Crombie's fifth national crown for the year, to go with her cross-country title last month and the track and field 1500m, 3000m and 3km steeplechase titles.
Her goal now is to qualify for next year's Commonwealth Games, either in the 1500m or 3km steeplechase.
She is yet to decide which.
Crombie has previously represented New Zealand at world cross-country championships numerous times, both as a senior and as a junior.
She has also competed in the World University Games in China and Turkey and so is fully aware of the climatic demands of the Commonwealth Games in Deli next year will pose should she qualify.
