The Bantams overcame Wigan, Arsenal and Aston Villa in a remarkable run all the way to Wembley, but Sunday's showpiece final did not have a fairytale ending as slick Swansea proved a Premier League side too many.
Nathan Dyer and Jonathan De Guzman struck twice each for Swansea and Michu lived up to his pre-match billing with another as the 5-0 scoreline secured Michael Laudrup's side the biggest win in Wembley cup final history.
But Phil Parkinson's League Two side have given the city of Bradford cause for huge celebration and inspired lower league clubs all over the world, and this was not lost on Duke as he reflected on his side's defeat.
"It's not just about the final," said Duke, who had the added disappointment of having been sent off early in the second half by referee Kevin Friend for tripping De Guzman in the penalty area.
"It's been the whole cup run going back to the first day of the season (when City won at Notts county in the first round).
"Every game through the rounds has been top-drawer entertainment.
"We're really disappointed with the result, but the overall achievement has got to be looked back on with real pride.
"It's not been achieved in the last 50 years and it might take another 50 years or even a 100 years before something like this happens again."