"You can, say, miss the No 2 control and go to No 3 but you must go back to it and then go to No 3 again," the 16-year-old said, explaining the loss of time would be critical.
For argument's sake, Fox was runner-up in the morning stage at Woodford House by a split second.
However, the teenager has a thing about finishing fourths, including two of them in the Oceania Under-18 Girls' Championship held throughout the lower North Island last week.
Fox is the 2013 champion having registered three first placings and a seventh with the two fourths and "a not very good 12th". She competed in the Oceania champs as a New Zealand representative in the New Zealand/Australia Challenge.
With elite Scandinavian and Aussie competitors often eclipsing her, Fox was chuffed to turn the tables on them for the first time as well as other national high flyers.
"I've competed overseas before but the terrains are different there with more rocks, and gum trees are not the same as pines."
Fox is jetting off to Portugal in April with her NGHS team.
Yesterday, Matthias Muller, of Switzerland, won the fourth stage to become the overall leader in the elite men's grade over 24 controls.
In the women's 22-control section, Hanna Raitanen, of Finland, clinched the fourth stage in the afternoon but countrywoman Venla Neimi is the overall leader.
Today, the Sprint in the Bay will be staged along Middle Road, Havelock North, from 10.15am and then at the village centre from 6pm in the final stage.
