However, his 3-8-3 score-card for the weekend was still enough to see him claim the runner-up spot overall.
Christchurch's Alastair Hoogenboezem came on strong at Taupō with a 2-2-1 scorecard and climbed from fourth to third in the standings.
With Mitch Rees winning his first national road-racing crown, and in the premier class no less, he followed in his 53-year-old father Tony's wheel-tracks.
Motorcycling New Zealand Hall of Fame inductee Tony Rees was national superbike champion three times, in 2017, 2005 and 2001, and was national open sports production champion three times, in 1997, 1998 and 1999.
This is in addition to him claiming numerous race wins in the street racing environment, Tony Rees many times the top man around Whanganui's fabled Cemetery Circuit and a multiple champion at the now-defunct Battle Of The Streets events in Paeroa.
But Mitch Rees' crowning glory on Sunday was also the first time that both a father and son had clinched a New Zealand superbike championship title.
"It was a fantastic weekend," Mitch said.
"Got pole and won the first two races. I knew what the mathematics were, although I obviously would have liked to win every race. To be fair, I was a bit lucky too because Damo had a really bad weekend.
"The bike was good in a vast range of set-ups for us here this weekend. Obviously Damo deserved to win the championship too, but only one rider can win and I stepped up this weekend and got the job done."
It was a case of mixed emotions for his 25-year-old brother Damon, happy for his brother but disappointed to miss out on winning the title.
"It's a bitter pill to swallow, but if I had to lose to anyone, I'm glad it was my brother. It was a good result for the team and good for Honda too," he said.
Class champions this season were Whakatāne's Mitch Rees (Superbikes), Christchurch's Dale Finch (Supersport 600 class); Napier's SJ Cavell (650 Pro Twins); Invercargill's Cormac Buchanan (Supersport 300 and Supersport 150); Tauranga duo Barry Smith and Stu Dawe (Sidecars).