The Scarlets youngster went on to tour Australia as part of interim coach Rob Howley's squad and figured in the uncapped midweek victory over Canberra Brumbies. But now he wants to take the next step and repeat his national stadium experience and appear in front of his home fans against one or all of Argentina, Samoa, New Zealand and Australia.
"The greatest memory from the Baa-Baas game was singing the anthem," said Williams who was again named in Howley's 35-man training squad after impressing on tour and putting in some scintillating performances for the Scarlets this season.
"Playing for Wales is something I've always dreamed of doing and I know certain players like to lock their emotions away and avoid singing but that was never going to be an option for me," he added.
"The game itself is a bit of a blur but it was obviously brilliant to get the victory and it was an amazing experience to be out there doing something I'd dreamed of since I was a boy.
"All my friends and family were in the stadium and the 'Waun-massive' will be there by the busload if I get a chance again.
"They are all waiting to see before they get their tickets, but that's one of the things that would make it really special as many of my friends don't necessarily come to see me at regional level as they are all playing in some form or another themselves.
"All I can do is work really hard at times like this in Poland when the coaches push you hard to get the best out of you and try to show that I can be an asset.
"I'm surrounded by a great group of players and I'm learning all the time off people like Leigh Halfpenny, who is a British Lion and a great player.
"I'm rooming in Poland with Alun Wyn Jones, who is the ultimate professional, he has really looked after me and he is a great room-mate.
"He always has the water bottles stacked up ready when you get back to the room after the day's training and he brought a four point adapter plug with him. I couldn't believe it, you can't get much more organised than that!"
Williams is on his second visit to Poland, after being involved with the training camp in Gdansk which prepared the 2012 RBS Grand Slam winning squad and he has a unique way of coping with the rigours of the infamous cryotherapy chambers.
"We play word association games to keep our minds off the cold when we are in the chamber but just to make it a bit more interesting we have introduced a forfeit where you have to do five squats in the chamber if you repeat a word or use a colour word, which are banned," added Williams.
"The dry ice in the chambers in Spala is particularly dense, its worse than the one in Gdansk and whilst its obviously extremely cold everywhere, it's even colder on the floor.
"The first forfeit we had was five press ups, but it was too brutal putting your head down there, so now we have settled for squats - I've had to do them a few times, but it's all part of the experience.
"November will be tough for everyone, but we are well prepared. It would be another dream come true to run out at the Millennium Stadium again and we have four great teams in opposition so there is everything to look forward to."