Rotorua's Jason Jepsen was the other challenger in the Premier 450cc class. He began the meeting on his Yamaha but switched to a stock standard borrowed Can-Am for the last two races after encountering gearbox problems.
Tauranga's Mark Goldstone described his opening ride in the Open Expert class was "a shocker" which produced a fifth place and then he dominated the racing with six wins aboard his Yamaha. Hawke's Bay rider Wade Taylor (Yamaha) was second and Scott Keegan - younger brother of Premier class winner Cameron - riding a Honda TRX400 was third.
Nick Sampson (Suzuki) won the Production 450cc title ahead of Brett Wilson (Honda) while KTM riders dominated the Veterans (40+) category with Craig Ridgely taking the title ahead of Allan Sharp.
The junior category winners were Matthew Wicksteed (Yamaha) in the 12-16 years class and Cullen Curtis (Yamaha) in 250cc Production.
Cooper (Suzuki) and Josh Coppins (Yamaha) will be joined by young Mangakino racer Kayne Lamont (KTM) in the three-strong team for the world teams event in Lommel, Belgium on September 30. It will be Coppins' last top-level ride having recently announced his retirement.
Meanwhile on Sunday at the penultimate round of the Australian MX Nationals at Moree, NSW Coppins edged out his lead in the Pro Open class over Suzuki's Todd Waters by a further two points.
Cooper made it two Kiwis on the premier class podium at Moree with a first, third and fifth placing on his Suzuki RM-Z450. He is still fifth in the championship standings but only 14 points behind British rider Brad Anderson (Honda).
"I felt really good all day until the last race - I just struggled to adapt to the hard-pack track in the final moto," Cooper said.
"The team has been working hard and I'm happy with the result."
Cooper eyes Europe
Papamoa's Rhys Carter - who had been in the running for a Motocross of Nations ride - continued to make a late-season impression on the Pro Lites (250cc) category.
On a borrowed Suzuki RM-Z250 Carter was making his second start in the Aussie series and finished 10th at Moree with a 11-9-11 scorecard. He finished equal on points with Queenstown's Scott Columb (Suzuki) and ahead of fellow Kiwis Ethan Martens (Yamaha) and Justin McDonald (Honda).
The final round of the Australian Nationals is at Coolum on Queensland's Sunshine Coast this weekend.
Busy time for Urwin
Tauranga kart racer Niki Urwin has a busy fortnight ahead of him.
Urwin competes this weekend at the fifth round of the Gen-i Kart Stars Rotax Max Challenge of New Zealand in Auckland having taken the points lead in the Masters class standings at the Te Puke round last month.
The following weekend Urwin is part of an eight-strong Kiwi squad racing at the Australian Rotax Nationals in Dubbo, New South Wales. Urwin, who is a paraplegic and races his kart with hand controls, will compete in the Rotax DD2 masters class driving for the Australian distributor of the Italian-made Formula K kart chassis.