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 Barclays Premier League side too many. The 5-0 scoreline secured Michael Laudrup's side the biggest win in Wembley cup final history.
But Phil Parkinson's npower League Two side have inspired lower league clubs all over the world. "It's not just about the final," said Duke. "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."
Duke, who was sent off in the final, added: "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."
The Bantams must quickly focus on a return to league action against Dagenham at Valley Parade on Wednesday night if they are to kickstart their play-off challenge.
"We haven't got much time now for reflection," Duke added. "We've got to concentrate on Wednesday now, but at the end of the season we'll look back on this and think what an amazing achievement it was.
"The fans needed to have a good day out. We tried to do it on the pitch for them, but you could see at the end with all the flags waving and the cheering and chanting. It just shows what fantastic support we've got and we just hope they've had a good day."
Striker Nahki Wells is targeting a return to Wembley in the play-off final in May as the Bantams aim to bounce back. "We'll keep our chin up and it's back to business on Wednesday in our league game," said Wells, who is on course to reach his target of 20 goals for the season.
City's cup run - they also won at Watford and overcame Burton in extra-time thanks to a 90th-minute equaliser - has taken its toll as Parkinson's side have won only one of their last eight league games to slip eight points adrift of a play-off place. But Wells was quick to turn his attentions to the Dagenham game and the chance to make up lost ground.
"I don't think it will be difficult to get up for the next game at all," he said. "Having just lost we want to put things right and show everyone what a good side we are. Wembley's out of the way now. We're going to enjoy the night and as of Monday it's automatic that we're setting our sights on coming back to Wembley."