The 25-year-old arrived at York Road a fortnight ago having made a surprise switch from Blue Square South champions Woking. Last season's title win was Duncan's second successive promotion having gone up with Ebbsfleet the year before.
The left back, who can also play in midfield, knows his move to a team who only survived relegation thanks to a reprieve has surprised some people.
But he says he saw enough of Maidenhead last season to know they have the potential to challenge at the right end of the table.
He said: "I know a lot of people have raised their eyebrows at the move but there are a lot of options you have to consider.
"I live in High Wycombe and have a young family to support. I could have gone to clubs in the Conference or Conference South but then not seen enough of my new baby.
"Maidenhead was the right option for me. It will be a challenge but the talent within the squad is unquestionable.
"We (Woking) lost twice against them last season. Both times we came off the pitch knowing we had been beaten comfortably."
Duncan added: "It's a young team with a lot of talent. I always like to aim high and I'm hoping to sneak a look at the play-offs.
"There are young, hungry players at Maidenhead with talent. All it takes along with that is team spirit and a little bit of luck.
"I really think we can have a good season. If I thought we would be struggling at the bottom of the table I wouldn't have considered the move."
Source: Maidenhead Advertiser