Williams was one of the heroes of that success as he crossed for a glorious 60-metre solo try but he insists his side face an even tougher test when they welcome French giants Racing Metro to Llanelli on Saturday.
"It doesn't get any easier. We know we're in a tough group and we knew that when the draw was made, but that's what you want," said Williams, whose team will also face last season's beaten finalists ASM Clermont Auvergne in the December double header.
"You want to play against the best teams because it's the only way to learn by putting yourselves under pressure.
"The Heineken Cup has brought the best out of our players. We spoke in the week about wiping the slate clean and it was our chance to show what we can do. That's what we did.
"Hopefully we can build on this win now. If we can do the same - or even better - then we'll be in with a chance next weekend."
The Scarlets scored three tries against the 2012 English Champions, with Rhodri Williams getting them underway before namesake Jordan matched Scott's individual effort in the second half.
Simon Easterby's side set a strong platform at the setpiece - something their head coach admitted they struggled with last season - and then kept the ball alive whenever they could through both forwards and backs.
And Williams was quick to praise his team's pack, hinting that the West Walians will look to employ a similar game plan against Racing in two days' time.
"I thought the boys were outstanding and the forwards really stepped up," added Williams.
"Even with 14 men, we were winning the scrums. I went in and there was a bit of laughing and joking after the scrums. All credit to them: over pre-season they have really worked hard at the setpiece.
"I thought the first half suited us. It was quite open and that's how we like to play. It was high intensity and maybe we've lacked that at the start of the season. The Heineken Cup is a different level - it was a great experience for the boys and it was a 1-23 performance.
"I was panicking at the end but we will learn from that. We haven't been in that situation before and it was good for us to see it out."
It was a good day all round for Williams, but it wasn't the first time he has left South West London with a huge smile on his face and plenty of positive headlines coming his way.
The 23-year-old scored the winning try when Wales beat England at Twickenham to clinch the Triple Crown on their way to the Grand Slam two years ago.
"Twickenham has been kind to me. We stayed in the Marriott and that's in Twickenham Stadium. Unfortunately, I couldn't see the pitch from my hotel room, but it's a special place.
"I know that try was two years ago and I can't keep living off that, but it was the first time I've been back since so it was pretty hard not to think about that day when we arrived at the hotel."