Koons, formerly of Dunedin, said a month-long break away from racing to concentrate on building endurance had paid off. Last month, he became the first New Zealander to achieve a Winter Olympic qualifying standard.
"I haven't raced since Finland and have been focusing on high-volume training to build an endurance base, he said.
Koons, who has dual US and New Zealand citizenship, bases himself in Maine during northern winters.
He skied at or near the front for the entire race and won by 13 seconds.
"It felt good to get back into racing, I am as fit as I've ever been and now need to concentrate more on speed work and fine tuning," Koons said.