Wales had seen a 17-9 lead whittled down to just two points when Williams scorched past four defenders and produced an extraordinary acrobatic finish to avoid the corner flag and ground the ball one-handed.

Replays suggested Williams' left boot may have caught the touchline as he launched for the line - but Italian television match official Carlo Damasco was satisfied, and Wales had their second victory of the RBS 6 Nations campaign.

"I would probably break my back if I tried that in training," Williams laughed.

"I know if you are anywhere near the chalk or touch the flag it is no try - and I was determined to score that try.

"I managed to break the line and decided to go round the full-back not step him. It was a squeeze in the end but I felt I had scored it.

"There's no doubt in my mind and I didn't find any paint on my boot. I got the five points and that is all I care about, to be honest."

Head coach Warren Gatland is building a reputation as a ruthless task master as he attempts to rid the Wales camp of complacency.

But within the honest environment he has created there is also room for heady praise when required, and Gatland reserved some of it for Williams after the game.

"Not too many rugby players in the world could have scored that second try that Williams got," said Gatland.

Williams' match-winning effort was his second of the match, after he danced around Scotland full-back Mike Blair to put Wales in front early on.

The diminutive Ospreys winger is now just three tries short of Gareth Thomas' Wales Test record of 40.

"It would be great to be the highest try-scorer for Wales," said Williams.

"Scoring tries does help with confidence but it is all about performing well and if you don't in this squad then you could be out on your ear."

That message was made crystal clear following the opening-round victory over England, when Williams' fellow winger Mark Jones and the loose forward Alix Popham were dropped from the squad altogether against England.