Williams, a Lions tourist in 2005 and 2009, has been denied his RBS 6 Nations swansong after being ruled out of this weekend's Championship finale with a knee injury.
It was a sad end to Williams' Championship career in which he has touched down 22-times.
But 1970's star Williams has led the tributes to his namesake Shane, who will draw the curtain on his glittering international career following the World Cup in September.
He reckons the Ospreys flyer has had more influence on the game than Wales and Lions wings Gerald Davies, John Bevan and Ken Jones, and is among Wales' true rugby greats.
"In the professional era he's [Shane] the greatest Welsh wing we've seen," Williams told the BBC.
"If he's the greatest Welsh wing of all time, well you can debate that. I'm not going to say that.
"But he's up there with the greats and we'll be looking back at his montage of tries over the next 20 years - you'll be going 'wow, look at those tries that guy scored."
"He's been a wonderful servant to Wales and he's saved Wales so often.
"When the games are tight it's been a piece of Shane Williams brilliance has been the difference between Wales winning or losing.
"And they're going to miss him enormously when he does hang up his boots after the World Cup because they've relied on him without ever mentioning it too much - that they relied on him a bit too much to score and to do things out of the ordinary.
"He's a brilliant all-round player who got involved enormously. He could change the game himself.
"And as a winger - and you can talk about Gerald Davies, John Bevan, the great Ken Jones, all these guys - they didn't have the influence on a game that Shane has had.
"He could run that game himself from the wing - that's very, very unusual to see that.
"Outside-halves or scrum-halves can run a game and they control it, but Shane is involved so much in these games with the Ospreys and with Wales and you can't say that about many other wingers of world rugby."