Duffy grabbed an assist as the Boys in Green were held to a 1-1 draw by Switzerland in a friendly at the Aviva Stadium in Dublin last night.
The Blackburn Rovers centre-back's previous cap came in a draw with Costa Rica in Philadelphia two years ago, but the 24-year-old says that this meant more given that it was on home soil.
"I was more ready for it now than I was two years ago when I played," Duffy told reporters after the game.
"I enjoyed it, playing in front of Irish fans for the first time was enjoyable, and I had goosebumps out there. It was a day I dreamed of, and I've got it."
His centre-back partner on the night Ciaran Clark opened the scoring for the Irish, who have qualified for Euro 2016, but it remains to be seen if Duffy will be involved in France.