In keeping with the ideology of pedigree players, suffice it to say the 52-year-old had played often enough to know that his name would be engraved on the honours board of the sought-after Hawke's Bay tourney.
The plus-three handicapper from Hastings Golf Club was a stroke behind Lachie McDonald, of Palmerston North, after two rounds on day one.
The break came in the third round the following morning on Sunday when McDonald blew out to 75.
Russell Mitchell, of Maraenui Golf Club, "wasn't far behind" but buckled under final-day pressure.
"Let's just say I didn't have to stress out too much in the last round," says Duff, a former Bay senior men's representative who thanked his coach, PGA professional Brian Doyle, of Hastings.
"Brian has been telling me something for 23 years and I've been trying to put them into place.
"He's fantastic. I'm seeing him every [few weeks] so he's a great coach not just on the physical side of things like swing but the mental side as well."
McDonald was runner-up, eight strokes adrift.
The stableford crown went to Richard Yovich on 146 points with Noel Stubbs two points behind in second place.
McDonald, says Duff, is a very good player and the contingent from Palmerston North added to a quality field.
But he feels the Bay lacks depth, juxtaposing it with the talent such as Doug Holloway, Pieter Zwart and Darryn Turley.
Duff opted to fly below the radar several years ago at the height of his prowess amid Golf Hawke's Bay's efforts to inject young blood in the ranks to boost the region's stocks for the premier amateur team tourney, the Toro Interprovincial.
No doubt Duff will not be part of the equation to the men's interprovincials to be staged in Invercargill from December 1-5 this year because he has made himself unavailable since the controversy.
While countless secondary schoolboys have sung Duff's praises as a cricket coach in his capacity as Lindisfarne College teacher, the former Central Districts Stag batsman doesn't see that filtering into golf even as a playing captain of the Bay rep side.
"When you're out there [interprovincials] we are playing our own game so you don't spend as much time with the boys so it's quite different from cricket."
Either way, it seems the young will be poorer for not having Duff to bounce ideas off or simply watching a bloke with a placid demeanour tame the tricky fairways and greens around the country.
Doyle likens Duff to "good old red wine that gets better with age".
"I have no doubt that Stu, even though he's unavailable, is the best amateur player in Hawke's Bay. He's a cut above the next rank of amateur players," says the former New Zealand high-performance coach.
Doyle says during his Bay senior representative days Duff was content with a par round but these days emulating that is a run-of-the-mill feat for the amateur.
"He just plays from the heart and is a sponge to everything I say. He has a professional air about him and youngsters I've spoken to and who know of Stu's prowess, I have urged them to pick his brains," says Doyle who believes Duff is a much better player now than when he was an interprovincial representative.
"He's got more strings to his bow and his confidence has grown. He also has excellent flexibility for his age.
"I do mental stuff with him. Actually we were just doing it today," he says, alluding to material he has gleaned from sport psychologists during his coaching stint at the national academy.