THE baby-faced 21-year-old with the million-dollar smile was basking in the glory of an electric opening to his international career.
Craig Gilroy makes a habit out of making history. He was the first player to touchdown at The Aviva Stadium on Saturday, July 31, 2010 when he had Paddy Jackson, Luke Marshall and Iain Henderson for company.
He was back to razzle-dazzle Argentina on the occasion of his first Ireland cap with blurring footwork, high-stepping his way around Nicolas Sanchez and Gonzalo Camacho for the try that injected instant belief into Ireland at the National Stadium on Saturday.
"We had our pre-called move. I knew my role in it. It was one of the options back inside. There was a gap. Johnny obviously saw that and put me away. Once I got the ball in my hands -- I don't really know -- I just turned it on," he said.
And he was gone. It was plain to the naked eye that Sexton saw in Gilroy a potent attacking threat that could be trusted to ask questions of Argentina's defence.
He was at the sharp end of moves too many times for it to be an act of coincidence. His strength is his speed and evasion. Ireland chose to go around rather than through.
"Ach, I wouldn't say I was central. There are countless plays and patterns that we do. I just have to know my role in them. I leave it up to Johnny and the rest of the guys to execute it. I just do my bit, see how it goes."
It was the first trickle that turned into a seven-try torrent as the self-belief literally coursed through the entire side. It is true. The exuberance and excellence of youth really is infectious.
"It's big opportunities. I just really want to take them, really eager to take them and it just sort of happens," he said.
It doesn't sort of happen. He makes it happen: "The last few years have been a bit of a whirlwind. But, it's been great. It is what I want to do. It is the career path I've chosen and I'm delighted things are going well. I hope they continue."
It was a day of dreams realised. There were so many highlights from the break of morning to the close of night. He just wanted to savour every second.
"The drive to the stadium, the fans -- the whole day was amazing. The anthem. If I had to say one, it would probably be the feeling after I scored the try. Everyone came around me. I don't think I will ever forget that."
The Six Nations looms on the horizon. Gilroy must be favourite to keep the number eleven jersey as Simon Zebo and Keith Earls will get pushed out wide by the returning Rob Kearney and Brian O'Driscoll, Luke Fitzgerald makes his way back and Andrew Trimble rebounds in the New Year.
Is the jersey his to hold onto? "Not at all. I don't feel like that in the slightest. I've only played one official game. It is really just a starting point. I've got to work extra hard and keep my feet on the ground and, hopefully, hold onto it."
The boy is doing just fine.