Just over a week ago, the 28-year-old had been named in the Republic of Ireland squad for their international friendly against Bulgaria, finally getting to make his debut when coming off the bench on the hour mark.
Collins certainly made the most of it too, stretching to volley home Enda Stevens’ left wing cross in the closing stages to make it 3-1, as on what his maiden international goal meant to him, he said: “Probably the best moment of my career.
“To play for your country and get your first cap and score, it’s what every lad wants to do as a kid.
“I’ve been lucky enough to fulfil that dream, so I’d probably say it’s right up there.
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“I think that evening and the day after, it came into my head quite a lot and I thought about it quite a lot.
“Then I flew back to my family and I celebrated with them, but then I came back into Luton on Thursday and trained Thursday, Friday as usual.
“You can’t really think about it too much as we had an important game (against QPR), so it will last long in the memory.
“But I don’t want that to be the end, I want to keep doing that for my country, so I’m hoping there will be many more to come.”
Collins almost hadn’t been featuring at all, as he was only named on standby by Mick McCarthy to begin with, included after an injury to Preston striker Sean Maguire.
He continued: “That’s why the manager names so many people in the squad, as he knows people are playing and injuries happen.
“Fortunately for me I managed to get in and the rest is history.”
After being involved with the Irish squad for the weekend and getting his chance on the field, Collins noticed a big difference in the standard that he was used to, saying: “The quality’s really high, you’ve got Premier League players there and the training’s quite tough.
“The opposition are the best in their country, so you’ve got be on your game and you can’t really slack off.
“You’ve got to be at it every day, every game and I think during my time away with Ireland we did do that.”
Team-mate Harry Cornick had been one of the viewing public on TV on as Collins had his moment to remember, saying: "It was brilliant, we were watching it and it's brilliant for him personally.
"He’s deserved that no end, he’s scored 20, 20 in the last two seasons and I know he’s started the season really well.
"He’s a born goalscorer and he’ll do it at any level I believe, so hopefully he can keep up scoring for us as well."
Finally, Collins completed an excellent few days by scoring his fourth league goal of the season at the weekend, although would have preferred to have beaten QPR instead.
He added: “It’s been a brilliant week for me personally, to score in the week for Ireland and then get another goal, as a striker it fills you with confidence.
“But this is a team game and I’d have much rather the three points.
"You can only get three points if you’re scoring goals though and hopefully I can continue doing that.”