Hampel started the meeting with a disappointing last place, but the home nation rider began to work out the track conditions and quickly moved up the standings. A victory in his third ride and two-second places ended his qualification heats with 8 points, and a place in the latter stages.
A win in the first semi-final for Hampel put him in the last heat ahead of Chris Holder who just edged out Krysztof Kasprzak. Joining the duo in the final were Tai Woffinden and Greg Hancock.
Woffinden came into the meeting having suffered a broken collarbone in the British GP, just two week ago. The Briton managed 8 points during the first stage of the meeting, which included two heats wins and two last places.
In the final, Holder made the perfect start, but a mistake on the second bend allowed Hampel to make the pass and surge ahead for his second win of the season – his first coming in New Zealand.
Hampel moves up to fourth in the standings with 66 points, while Holder moves up to 68 points and Woffinden is second with 73 points.
Emil Sayfutdinov remains at the top of the standings with a 15 point score. The Russian dropped just one point during his programmed rides, he added a further point to his score with a third place finish in the first semi-final.