The event was held at the Bruce McLaren Motorsport Park, in Taupō, New Zealand from 4 to 5 February 2017.
Thomas Randle continued his front-running form by achieving the fastest time in four out of the five practice sessions during the weekend.
Armstrong grabbed his first Toyota Racing Series pole position with a time of 1:23.383, with Jehan Daruvala in second and Brendon Leitch in third.
A strong start followed by fast, consistent race pace meant that Leitch would grab his first race win of the year.
Pedro Piquet held off a rampant Thomas Randle to take his second win of the year, with Daruvala in third.