The 17-year-old, who has come up through the ranks at Kenilworth Road, had played for the first team once before, that in the final minutes against Exeter City last season, but this time he was in from the start against the former Championship heavyweights.
On his journey so far, Justin, who admitted his boyhood hero at Luton had been a certain Kevin Nicholls, said: “It’s one I’ll remember for the rest of my life, it was excellent, just crazy. I’ve been here 11 years, since I was seven, because I used to play a year up when I was seven, in the under nines.
“It’s what everyone dreams of really. (To be) a professional footballer, playing in the first team, in front of a great crowd. It’s just what you live for.”
The youngster had time to get used to the fact he was going to be playing in such a big tie, after Dan Potts was sent off at Plymouth on the opening day and Alan Sheehan pulled out injured too.
He continued: “I knew I was playing early in the week because Pottsy got injured and I’m a fill-in full back.
“I kind of knew a bit about Aston Villa because we might have played them last year in the FA Youth Cup, but it never came round to it. But I had some knowledge there, so it helped me in the game.”
Having Villa, who had the likes of £12m striker Ross McCormack in their ranks, was one thing, but with the game live on the Sky TV cameras too, Justin admitted there were nerves before the game, but they quickly went once the whistle was blown.
He said: “I thought about it a lot before the game, but when you’re out there you just focus.
“The lads help you and bring you up to their level. You’ve been training with them so they all know you. They know your strengths and weaknesses, help you out and we’re all a team.”
Being born and bred in Luton, Justin had an extra incentive too with plenty of his friends and family in the crowd, as he said: “They made the long trip to Plymouth even though at the start I wasn’t on the bench, then I got on the bench in weird circumstances, but they back me to the hills and back. It’s nice.”
It had looked for a second that Justin might not complete the match, as he went down with cramp midway through the second half, but recovered to ensure he stayed the distance.
He continued: “It was crazy. I’ve never had it before in a match, my leg just locked up. I didn’t know what happened.
“I got supplements from the side, kept on going and just had to get through it.
“I wouldn’t have liked to come off, even though I was struggling a bit. (It was my) full debut and I’d have Iiked to get through it and liked to play well and I think I did that.”
Play well he did do as Justin’s evening was capped off by picking up the man of the match award from the sponsors, as he added: “It’s always great to get individual honours but in the end it’s all about the team.
“We’ve got a great group with a never say die attitude. You know how it goes; the gaffer drills it into us so, when we’re behind, we never let our heads drop.
“We just kept on plugging away and we knew we had the quality to get chances and if we take them we’ll end up doing well.
“It could have went the other way as well but we did enough to win the game and win it comfortably.
“I think our counter attacking play was quality. “We defended well and that’s all it takes. As long as we’re through to the next round that’s all that matters.”