However, Cooper was perhaps surprised by the power-packed potency of Australian KTM team riders Ford Dale and Kirk Gibbs who had made the trip across the Tasman to tackle Woodville on Sunday.
Dale won the first two MX1 class races of the day and looked odds-on to wrap up the MX1 crown and perhaps to win the Invitation Feature Race as well - the race that has the NZ GP crown as its prize.
But Cooper came on strong in the feature race to catch and pass fast-starting Dale and then build up an eight-second buffer before the finish.
That was job one complete, the GP title tucked away.
Dale again looked comfortably positioned in the day's third and final MX1 race until he dropped out with painful wrist cramp, leaving Cooper and Gibbs to battle for the win.
Again Cooper managed to force a way past the Australian visitor and set off over the horizon, with Taupo Suzuki hero Brad Groombridge snatching the runner-up spot. So that was Cooper's second job complete, consistency putting the MX1 class win in the bag.
"Consistency has always been one of my downfalls in the past ... but perhaps not now," Cooper declared afterwards.
"It was very hard to pass on this track and I wasn't getting good starts. You really can't sprint on this track because it'll bite you."
The final overall MX1 standings had Cooper on top, Groombridge in second and Gibbs third, with two-race winner Dale, one of the fastest men on the track, unfortunately forced to accept fourth overall.
Rotorua's Michael Phillips (Honda CRF450) twice finished sixth in the MX1 class on Sunday but a crash during the feature race prematurely ended his day.
The MX2 (250cc) class at Woodville produced a surprise winner with Mangakino's Kayne Lamont (Husqvarna TC250) - just recovered from surgery and riding a new bike for a new team - won the day with 1-3-2 results, finishing ahead of Rotorua's John Phillips (Honda) and Dargaville's Hamish Dobbyn (KTM).
Phillips (The Honda Shop Racing CRF250) finished 5-1-5 in his three MX2 outings.
Lamont also took one of the new Husqvarna Red Bull New Zealand Racing Team bikes to win the stand-alone Roddy Shirriffs Memorial race, for riders aged under-22 years.