At 22, Duke was still playing Sunday league football, in addition to turning out for Matlock in the UniBond League Division One.
A trial at Sheffield United turned into the prelude for a career largely spent in the lower leagues, apart from one part of a seven-year stint with Hull when Duke found himself as the first-choice Premier League keeper.
But it is only this season that Duke has really come to prominence.
His penalty shoot-out heroics against Wigan and Arsenal on Bradford's run to the semi-finals, and then two outstanding displays in an amazing triumph over Aston Villa to reach Wembley have shoved Duke to centre stage.
Which just shows in an era where the easy option, even below Premier League level, is to look overseas, there is plenty of talent further down England's extended pyramid system.
"I was playing for Matlock and Sunday football as well, but in that summer I got a trial at Sheffield United and it has gone from there," said Duke.
"It just shows there are a lot of players out there who can still do it.
"I was fortunate enough to get the break and I have been prepared to put the hard work in to improve myself."
Duke's determination to succeed on the pitch was matched by his bravery off it in 2008 when the Sheffield-born stopper discovered he required surgery to remove a testicular tumour.
Although he was only out of action for three months, the cancer scare provoked a change in mindset, which may come in quite handy on the biggest weekend of his career.
"It gives you a bit of perspective," he said.
"When you are having a bad day, you don't let things worry you too much.
"It is about ensuring your lows are not too low and your highs are not too high. As long as you have your health and your family and your kids are healthy, that is the main thing."
And that underlines why Duke has not allowed himself to get carried away by all the plaudits that have been coming his way in recent weeks.
"Football has a nasty habit of kicking you in the teeth," he said.
"The moment you walk onto the pitch thinking you are the hero, things will turn completely the other way.
"It is important to enjoy the feelings but you can't let it go to your head because you might have a big mistake in you.
"We lost 2-1 at Wimbledon last Saturday. If that doesn't bring you back down to earth nothing will."