The Scarlets full-back was in the form of his life during the tournament in France and he cut reigning champions South Africa to threads as Wales reached the final for the first time.
That performance led All Blacks legend Sean Fitzpatrick to compare Williams to Cullen and Welsh record try-scorer Shane Williams.
The 19-year-old, who has only started two games for his region, admits he has a long way to go but he thrives on the pressure of the tag.
“It was nice to have had those comments from the Junior World Cup,” said Williams.
“I heard a bit and it was good to have some of those comparisons with the greats that have played the game, to be mentioned in the same bracket.
“The comparisons do create a bit of pressure, but I thrive on it. When people expect big things it drives you on. Hopefully, I’ll have a run of games in the pre-season friendlies and kick on from there.”
Williams has previously been utilised at fly-half for Llanelli but he prefers the time on ball and space to attack from full-back.
He is set to be handed plenty opportunities in the Scarlets’ back-three following the departures of top scorers Andy Fenby and George North.
And he knows all too well that he must bring greater consistency to his game.
“I prefer to play full-back,” said Williams.
“There’s more space and time on the ball and less pressure than having to control a game at ten.
“It’s probably the biggest thing in my game, to be consistent. I have patches in games where I lose form or concentration. Hopefully, I can sort that out this season.”
