Later that afternoon, he led from start to finish in the first of three superbike races planned for the two-day event.
He crossed the line an impressive 6.5s ahead of second place, Christchurch's Alastair Hoogenboezem, that result sending an early warning shot to his superbike rivals.
The 23-year-old had more of a fight on his hands in race two the following day, with seven riders battling for the lead early.
Positions at the front changed hands several times before Rees could again break through and then break away.
"I had a terrible start in that second race and, with riders to my left and to my right, it was quite a battle. It was very busy.
"I got to the front and then pushed hard to create a gap. I was actually deteriorating physically near the end, struggling with my sore shoulder, but I held on for the win."
Runner-up to Rees in race two, crossing the line 4.5 seconds behind, was his older brother Mitch Rees.
Unfortunately for Rees, he never got the chance to further bolster his overall points advantage with the event cut short following a major oil spill during the weekend's second of three sidecars races, shortly after midday on Sunday.
The event organisers decided, "in the interests of rider safety", that the meeting was "declared" and further racing was therefore cancelled.
Rees now enjoys a 15-point advantage at the top of the superbike class standings.
Hoogenboezem ended the weekend on the second podium step, thanks to his 2-3 score-card, while Mitchell Rees finished 4-2 to claim the third podium spot.
What made Damon Rees' performance more remarkable was that he was a virtual novice on a 1000cc bike after making his superbike debut only last season, at round three of the nationals at Hampton Downs in March.
Other class leaders after the weekend's abbreviated event are Palmerston North's Jacob Stroud (Supersport 300 class); Pāpāmoa's Leon Jacobs (250 Production class); Christchurch's Chris Huddlestone (Superlites); Christchurch's Andrew McLaughlin (650 Pro Twins); Australia's Yanni Shaw (125 GP); Hamilton's Jesse Stroud (GIXXER Cup); Christchurch's Dennis Charlett and Will Clim (sidecars).