Whibley (Yamaha YZ450F) crashed on just the second corner of the race, the slippery grass catching him out and sending him sliding along the turf, effectively making him last away as the entire field of riders disappeared into the distance.
But, even in blinding conditions and with early leader Adrian Smith (Yamaha YZ250) setting a hot pace, Whibley kept his cool.
Surprisingly, at the end of the opening 25-minute lap, it wasn't fellow Kiwi international Smith, the national cross-country and enduro champion from Mokau, who came back into sight first - it was Whibley.
It was phenomenal, but Whibley had indeed powered past the entire field in less than half an hour. Smith was second, Hurley third, Stratford's Karl Roberts (Yamaha) fourth and, at that stage, the chasing bunch still within sight of Whibley's rear wheel.
That didn't last long and, by the end of lap two, Whibley had dramatically stretched his lead and daylight was in second place.
Hurley then found a way past Smith, who crashed soon afterwards as reduced visibility made life difficult for him, although Smith picked it up to hold on to third place
Roberts finished fourth, making it three Yamaha riders in the top four. Whibley won the over-300cc classification and Smith's third overall was also enough to give him the under-300cc class win.
"I rode pretty hard at the start but backed it off to cruise a bit at the end, although I had Daryl fairly close and that kept me focused," said Whibley afterwards.
"It was good to have that pressure from him. That's what I need for my USA build-up."
