The tougher conditions allowed Auret to fully utilise the horsepower of his LS7 corvette powered truck to maintain his advantage.
However, the former national champion felt prouder about his morning session where there was more of a level playing field with the other trucks, on a course which is easier for them due to be tighter and more technical.
"We sort of made one mistake in the morning and the afternoon, but we pulled that back with everything else," Auret said.
"But I was thrilled to get a win on a course that doesn't typically suit us."
Auret is now firm favourite to regain the national title as his main rivals on the overall points table had a bad day.
"The two guys - Scott Biggs and Greg McDell - were tenth and eleventh, it's given us a big buffer"
The Aucklander Biggs had been hoping for a good round so he could drop his 11th placing at the previous South Waikato round from his final tally, while McDell, who was second that day, had been on the climb.
The final two rounds in New Plymouth and Palmerston North are on more open courses which suit Auret's truck with the grunt he has under the hood.
"I feel gutted for [Biggs], he's just as keen for [the title] as I am," Auret said.
"All we need is another top five and I think we've got it."
In the Class C competition, Whanganui's defending national champion Kevin Hermansen came third in his class for the second round in a row, which was enough for 13th overall, with 709.43 points, behind Wellington's title contender Phil Conwell (524.54) and Bay of Plenty's Nathan Fogden (665.74).
Whanganui's Grant Harrison finished seventh in class and 25th overall with 916.05 penalty points.
The fifth round will be hosted by Mt Egmont 4WD in Uruti, Taranaki, on March 11.