"The top line was probably even with the bottom for the first five or 10 laps, but then the bottom was definitely better for the rest of the race.
"Lapped traffic seemed to mostly be on the bottom and that meant you had to run on the top to get past.
"I had to run 110 per cent up the top just to get by, because if you don't, the guy behind will.
"It was more a case of picking your moments of when to pass lapped traffic and when not to.
"It was a bit stop-start to begin with and I made a couple of mistakes, but probably about 20 laps in, I started to get into a groove and the car got better and better as the track went away."
Pickens was visibly pumped up after taking the chequered flag and securing arguably the most sought-after win in New Zealand speedway racing.
"It is the hardest race on the calendar to win — for one, it's the longest, but it has the most competition here. It's the biggest race in New Zealand. The New Zealand title is big, too, and it's very prestigious to win, but this has the toughest competition."
Courtney, who led early on, pushed Pickens hard for the majority of the race but faded in the final laps and was a comfortable second.
Larson started from the fourth row and took a while to move up but eventually showed his undoubted class to pick his way through the field. He had too much to do to catch the top two but took a well-deserved third place.
He and Courtney will now head back to the United States for the famous Chili Bowl meeting next week.
Keaton Dahm took a start-to-finish win in the sprint car feature in what was a convincing performance.
Behind him, a close battle between Daniel Eggleton, Matthew Leversedge and Dean Brindle saw cars swap places throughout the race. Eggleton eventually claimed second, with Leversedge third.
Tom Callaghan secured a superb feature win in the F2 Midgets, smashing the field by more than four seconds.
Ryan Baker made it back into victory lane in the TQ feature as he claimed a dominant win over Ben Morrison.