The tousle-haired blonde also tackled the top boys in America, riders who will no doubt go on to become some of the sport's high-profile and highly paid superstars.
Although a year younger than some of her male rivals, Duncan finished third overall in the 85cc to 150cc stock class - her 3-2 results earning her the podium spot. And she finished the event ranked fourth overall in the 85cc to 150cc modified class after finishing 3-5 in her two outings. "She could have been on the podium there too but she crashed while running in third in the second race and had to settle for fifth in that race," Turner says. "But I don't care where she finishes really, so long as she doesn't get hurt."
Turner was her mechanic and support crew and also there to give Duncan the occasional reality check. "I don't really think she could have done any better than this. I certainly never expected her to be running top-three against the boys here. These are all factory riders and teams she is up against, some of them operating tricked-out $40,000 bikes. It's pretty unreal. We were just doing everything from under a small tent."
Duncan was due to race one more time in the open class, hoping to back up her runner-up finish from the first race, but she decided that discretion was the better part of valour and opted not to race. "I hurt myself a bit in one of my races yesterday and decided not to risk hurting myself further," says the Year 11 pupil from East Otago High School in Palmerston. That meant she slipped back to finish the event 23rd overall in the open class, but, as she points out, "I was happy that I had done all I needed to do here."
When Duncan wrapped up her first New Zealand Junior Motocross Championships title in Tokoroa in April, it was one of the sweetest moments of her career. That weekend she became the first female to win the New Zealand junior 13 to 16 years' 85cc title.
Now the whole world knows about Courtney Duncan.