The Everton defender will lead the Boys in Green against Denmark but conceded that his main goal is to earn a call-up to Giovanni Trapattoni's senior squad
The 21-year-old will lead Noel King's charges in the friendly fixture against Denmark in Fredericia today, Friday, May 31, but admits that his intention is to make a return to the senior squad.
After a season which saw him make his debut for Everton, Duffy was called up to the senior Ireland squad in May 2010 by Giovanni Trapattoni, and the centre back is hopeful that he can catch Trapattoni's eye once more.
"Having been part of the full squad as an 18-year-old, my ambition is to get back there," he told the Irish Independent.
"The Ireland team has changed a lot since last summer's Euro finals, but I can't complain about not being in the squad – as much as I'd like to be part of it.
"I've just had my worst season, in terms of lack of games, so I didn't expect call-ups."
Duffy also revealed that he had no issue about turning down an invite to Everton club-mate Darron Gibson's 'stag party' in order to captain his country against Denmark, emphasising his love for playing for the Boys in Green.
"I'm dedicated!" joked the defender. "To be serious, though, this is our last warm-up game before the European qualifiers start in August against the Faroe Islands.
"I love playing for Ireland and there was never any question of me not showing up. I could do with a game, too," he added.
Republic of Ireland under-21s will take on Denmark today, Friday May 31. Kick off 15:00 BST.