The 17-year-old, who won the Italian Formula Four title last year, took the lead from the start and was not headed in the race for the historic trophy which dates back to 1951 and whose past winners include Bruce McLaren, Jim Clark and Stirling Moss.
"It was a hot race. I’m overwhelmed," an ecstatic Armstrong said. Track temperatures reached 33degC for the 20-lap race.
"It’s great to do it in front of family and friends," Armstrong said.
Armstrong got the better of pole-position driver Robert Shwartzman and was never headed. The 18-year-old Russian’s initial launch was good, but then his car seemed to bog down and Armstrong got half a car-length in front as they accelerated to the first corner side by side, where Armstrong emerged in front.
"I’m really happy for Matt Hamilton, who was my driving coach, as he won the trophy, too," Armstrong said.
Armstrong heads to Teretonga in Invercargill for the second round of the series with a 16-point lead over Shwartzman. Richard Verschoor, who won Saturday’s preliminary race, is a distant third after failing to finish the Lady Wigram Trophy event. Initially third, Verschoor battled past Shwartzman at the halfway point, but neither was able to get close to Armstrong at any stage. A puncture scuppered Verschoor’s chances on lap 13. The final place on the podium was taken by London’s James Pull, who held off a strong attack from Invercargill’s Brendon Leitch. For a time the Englishman looked as if he might challenge Shwartzman, but dropped back after making a couple of mistakes.
"Those cost me a lot of time and then I had to fightoff Brendon."
Earlier, Armstrong won the preliminary race from Verschoor and Shwartzman, while Pukekohe’s Taylor Cockerton had a good drive to finish fourth.
