It was not the result Holger Osieck and his players wanted, going down 3-2 to Japan in their second 2013 East Asian Cup match at Hwaseong Sports Complex.
But Duke, who made his debut in the 0-0 draw against South Korea on Saturday, could not hide his delight at opening his account wearing green and gold, by scoring Australia's first as they came from 2-0 down to level at 2-2, before conceding to lose the match.
"The greatest feeling in the world," the Central Coast Mariners striker said when asked how it felt to find the back of the net for his country.
"My first goal at international level - It's been a great experience, (I) love it."
Duke felt Australia showed a considerable improvement from their match against South Korea, pressuring Japan in key areas and ultimately being unlucky not to earn a point.
"In our first hit-out it was a bit difficult," he said.
"Our first game, we'd had that break (between competitive fixtures). So we got that first game out of the way and then came into this game with a different mindset.
"We knew what we had to do, get on the ball more, it worked out well for us and were just unlucky with the result unfortunately."
Substitute Mitch Nichols set up Duke for his goal and is now hoping to get on the pitch from the beginning in the final game against China on Sunday.
"Yeah, I was happy to get involved," the Melbourne Victory man said.
"(I) just try to do all I can do, I think (I) did that and can build on that.
"Hopefully I put my hand up for a start next game and go from there. It's the first 30 minutes I've played since August. It's been a good camp and hopefully we can end it on the right note."
