Mr Wishnowsky said the fire was already burning strongly when crews arrived, and was spreading over 10 hectares of land.
Firefighters had to contend with "very rough hill country", which became difficult to navigate as night fell.
"It's very rugged, hilly terrain. It got dark pretty quickly - and it was dangerous for the guys who were unfamiliar with the land when they couldn't see in front of them."
A new crew relieved their colleagues at daybreak - and their job wasn't any easier, thanks to the dry grass and strong wind gusts.
To make matters worse, crews had no help from helicopter support services, because of the wind.
"The wind is our biggest enemy at times like this," Mr Wishnowsky said. "It was very demanding."
Mr Wishnowsky said the fire was started by wind blowing vegetation on to nearby powerlines.
In the dry conditions, it would have taken "just one little spark" to start an inferno.
"A shrub had been blown through the powerlines - when we got there, it was still arcing in the wind, and dropping burning pieces everywhere."
He said firefighters were yet to survey the extent of the damage - though a nearby farmer had lost several fences and "miles of grassland".
"That will have an impact - that grass will take a while to recover."