At Meremere, Minnell and new navigator Louise Blythe finished runnerup in a new Superboat they put together at short notice, with Whanganui's Rob Coley and Kellie Minnell coming third.
Hamilton's Glen Head picked up where he left off in the final round of last season by claiming the crucial first-up victory.
After the retirement of Whanganui's NZ1 Pat Dillon, the race for the championship is wide open again, especially as seven-time world champion and basically the Godfather of superboat racing - Peter Caughey - had a massive crash at Meremere in his first big roll in 26 years.
Minnell said it was a dag to have picked up the second placing, given he was not going to do the series in order to focus on his new track, which is why wife Kellie has teamed up with Coley - the pair also coming Superboat runners-up during the recent Australian season.
However, with the high profile nature of this summer's events due to the different venues being used and both the national and world titles up for grabs, Minnell knew competing would also bring attention for his track come February.
"Hence, then, I thought I better get a boat.
"I wasn't going to be running, I was going to have the [national] season off and maybe run the worlds with my son."
What had often been a two-horse race between himself and Caughey was now perhaps a five-horse sprint including Head and Coley - both often "win or crash" drivers in the past - who have really honed their skills in the past two seasons.
"I think both of them, Superboat wise, you've got Rob going to poke his nose up there, and Glen's in a new package from Peter Caughey.
"It's probably going to be one of the hardest seasons, attrition wise."
In addition, Whanganui's former Group A national champion Richard Murray has taken over Dillon's PPG Hulk, which he now calls the Meaner Machine.
Dillon had lined up an Auckland buyer at the end of last season, who he would then mentor, but Julia Murray said the deal fell through.
"He just didn't come up with any money, and Paddy chased him and chased him.
"Richard, [because] it's a Ford, said he'd take it."
While a former Group A champion driving the proven Superboat championship-winning boat makes Murray another contender, he learned there is a massive difference in horsepower with sixth place in Meremere, also having a big roll during the day.
Julia Murray said on certain corners in a Group A boat you're used to just putting the foot to the floor - whereas Superboats need more precision.
"Any racer going to one class to another, they got [to get] used to that pace.
"Richard has said he has gained new respect for the Superboats."
The 400's series has been renamed Group B for this season but Whanganui's defending champions Ross and Shane Travers in their 500hp Radioactive boat want the same outcome, which Ross Travers believes will be harder as there are plenty of new boats looking to catch up to their engine package.
"[Defending's] a bloody sight harder than earning or winning it the first time."
At Meremere, Travers finished third behind Te Awamutu's Patrick Haden and Owhanga's Tim Edhouse after a spark plug lead came off during the final Top 3 shoot out.
"In the Top 3, I knew I could get another quarter to half second [faster]. [But] we had to race on seven cylinders.
"Even then, we were only half a second off finishing second."
Despite the mishap, Travers was still happy with third at his "bogey track", as last year he won five of the six rounds but came 10th at Meremere due to a wrong turn.
As the world championships are only for Superboats and Group A's, Travers said they will put a more powerful engine in Radioactive and move up a grade for those two events at Meremere on January 24 and Baypark the following week.
He would be rapt to finish in the Top 5 and has plenty of confidence.
"Going off our [Group B] times last year, we would have finished third overall [in Group A]."
Whanganui's all-girl crew of Donna Thomson and Monica Couper, "Two a Breast", continued their good form at Meremere from last season, finishing fifth on the day.
The other local competitor to this grade is the former national champion Hayden Wilson.
In the Group A class, Gisborne's Blake Briant picked up the win in Meremere, with Hamilton's Ric Burke second and Taupo's Warren Farr third.