But seven days later and everything was reshuffled at round two, with Rees on top and able to reflect on a massive 18-point lead over the new No.2 man in the superbike class standings, Christchurch's Alastair Hoogenboezem (Honda CRB1000RR).
A disastrous day at Invercargill saw Frost (Suzuki GSX-R1000) slip back to third overall, nine points adrift of Hoogenboezem.
Rees will be looking to push on with his winning momentum when the second half of the season gets underway at Taupo this Saturday and Sunday and then hope he can stay out of trouble so that he might collect the national title at the fourth and final round at Hampton Downs, near Meremere, a week later (on March 4-5).
It was tough for Wellington refrigeration engineer and father-of-three Frost to accept his fate at Invercargill, but, even though he saw a 10-point surplus transform into a 26-point deficit, he is still putting on a brave face.
"I love the Taupo and Hampton Downs tracks and I've been on lap record pace there. I will just work now on being as prepared as I can be and, although I guess I'm now in the position of underdog, I'll just ride as hard as I know how in every race that's left."
Also joining the superbike action at Taupo this weekend will be British rider James 'Flick' Flitcroft, Californian visitor Jason Aguilar and Te Awanga's Eddie Kattenberg.
"The more the merrier," said national superbikes' sponsorship and promotions manager Rob Cochrane.
"Eddie is a legend of our sport and, riding a 1198cc Ducati, he will be sure to keep the Bears (non-Japanese bikes) fans happy."
Meanwhile, in the 600cc supersport class, Wainuiomata's Shane Richardson (Kawasaki ZX6R) leads the way from Rees' 21-year-old son Damon Rees (Honda CBR600RR) and it will likely be another dogfight between these two men at Taupo this weekend.
Third in the 600cc standings is Rangiora's Jake Lewis (Triumph 675), another reason for Bears fans to be watchful.
Racing is tight too in the various other bike classes where the leaders are Invercargill's Jeremy Holmes (1000cc superstock class), Taumarunui's Leigh Tidman (Superlites), Christchurch's Andy McLaughlin (Lightweights), Christchurch's Dennis Charlett (Pro Twins), Christchurch's Matthew Hoogenboezem (125GP), Ashburton's Paul Skinner (Senior Development class), Christchurch's Jackson Cotton (Junior Development class) and sidecars pair Spike Taylor (Masterton) and Robbie Shorter (Tauranga).
There are now just six more races to go for each class, at Taupo and then at the finale at Hampton Downs on March 4-5, and anything could still be possible.