The 21-year-old scored the vital five-pointer in Saturday's 16-9 win over France - with the win sealing the 6 Nations Grand Slam crown for Wales.
Cuthbert had capitalised on a turnover to step inside Julien Bonnaire and beat another three defenders on his way to the line.
The score was Cuthbert's third in six Tests for his country, and his ever-more assured performances ensured that George North was not the only Wales winger that opposition defences were worried about.
But at the start of the season 6ft 6in Cuthbert had simply been looking to break into the Cardiff Blues team after impressing during a spell on the HSBC Sevens World Series circuit.
But once he appeared at regional level his combination of pace and power made him impossible to ignore and he found himself winning his first cap in the December defeat to Australia.
And Gloucester-born Cuthbert, who qualifies for Wales through his Wrexham-born mother, says he has found it difficult to come to terms with how quickly his career has moved forward.
He said: "I do have to pinch myself sometimes.
"At the start of the season I would never have thought that this would happen but I was given the chance to play for the Blues and I have taking it and I am loving every minute of it and hopefully I can develop and keep getting better as a player.
"Winning the Grand Slam has not sunk in at all, I haven't had a chance to think about it really as I am back with the Blues now, but maybe at the end of the season I will realise what has happened."
While the full scale of what he has achieved may not yet have dawned on Cuthbert, he has a clear recollection of his crucial score against Les Bleus.
He said: "I saw Dan Lydiate knock down Thierry Dusautoir and Alun-Wyn Jones win the ball. Dan was there to move the ball away and the call was for quick hands. I saw the space and it opened up and I couldn't believe it when I scored.
"There was no space initially so I stepped in, saw the gap and went for it. The boys did awesome and we were delighted to get the win and Dan had a brilliant game."
Cuthbert also caught the eye with his exuberant celebrations at the final whistle, repeatedly bounding into the air as Rhys Priestland hoofed the ball off the field.
And he admits the thrill of the moment got to him.
"It was just the excitement," he said. "Winning the Grand Slam is a big thing and it doesn't happen very often and my emotions overtook me a bit."
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