Australia have one foot in the knockout phase after one of their greatest ever victories, their first opening group-stage win since 2006, on Saturday night (Sunday AEST) at Vancouver's BC Place.
Irankunda became Australia's youngest World Cup scorer with a wonderful goal in the 27th minute among a magical, explosive hour, before Connor Metcalfe sealed victory with a glorious solo effort in the 75th.
"It's epic. It's unreal. Like, it's a dream come true," Irankunda told SBS.
Irankunda later added to media: "That's just what our team is all about: we fight for each other, and we just want to show the world that we can do something special
"A lot of people don't believe in us, but we have to believe in ourselves, and that's all that matters at the end of the day.
"I didn't think I would score on my debut, but I knew one day ... that I was going to score in a World Cup, and it came so quick."
The win sets up an enthralling clash with co-hosts the United States, who beat Paraguay 4-1 and lead Group D ahead of Australia, in Seattle on Friday.
But there will be one concern, with striker Mohamed Toure pulling up sore in his left calf.
Popovic, who became the first Australian to play and coach at a World Cup, was rewarded for his bold calls to start Irankunda and pick Patrick Beach over captain Maty Ryan and Paul Okon-Engstler over Jackson Irvine.
"They were maybe shocks for a lot of people, but not shocks within our playing group or staff," Popovic said.
Irankunda was "super nervous" in the lead-up to the match.
"I was struggling to sleep when I first found out that I was going to be starting,'' he said.
"It's a very nerve-racking moment, knowing that you're going to be starting in a World Cup in the opening game, and I was a bit scared."
Socceroos staff calmed a "scared" Irankunda down in the warm-up, and Popovic also spoke to him at the first drinks break about keeping his head.
"That's what they told me to do: go out there, have some fun, and we had a lot of fun today," Irankunda said.
Turkey captain Hakan Calhanoglu had incensed the Australians by saying Turkey were a more talented team.
"They came, they did their talking, but they couldn't back up on the field, and we got the win at the end of the day," Irankunda said.
"Obviously that gave us fire in our belly.
"It obviously did piss off a few boys, but at the end of the day, these guys can talk all their shit, so we don't really care."
For Irankunda's goal, Â Okon-Engstler lofted the ball to the attacker, who with a brilliant first touch took out Merih Demiral, before finishing beautifully.
"It just fell front of me, and then my body just started doing what it does. I didn't control anything, it just happened, and after I scored, it was crazy," Irankunda said.
"It was all instinct."
Irankunda ran to the corner flag and "boxed" it, in a pre-planned tribute to the famous celebration of Socceroos great Tim Cahill - his idol growing up.
"Timmy Cahill was my biggest inspiration in Australian football, and I look up to him, and I want to be like him one day," Irankunda said.
There were 10 World Cup debutants - with Harry Souttar the exception - in Australia's youngest ever starting line-up at such a tournament, with an average age of 24.6.
The magnificent Beach made eight saves, including stunning efforts to deny Abdulkerim Bardakci on the half-hour mark, then Real Madrid star Arda Guler in the 57th minute.
"It's something that we've always seen, and I've got a lot of belief in the young man," Popovic said of Beach.
"He stood up today, so very happy for him."
Irankunda also sang the keeper's praises.
"He saved us, he kept us in the game," he said.
Between Beach's heroics, Metcalfe went on an incredible weaving run before skidding an unstoppable shot inside the near post.
Australia's brilliantly desperate defence would not be bested from there.
