Thomas will be making only his second Test start after head coach Warren Gatland took the bold decision to change his entire front row following the victories over England and Scotland.

Former Wales captain Kingsley Jones has questioned Thomas’ ability to cope with the power of Italy’s renowned scrummagers after he struggled against South Africa last November.

But after a week of physical training - the like of which Williams has never before experienced - the veteran flanker dismissed Jones’ concerns and gave the Welsh front row a ringing endorsement.

“The pack is a strength of Italy’s game but our boys are capable of stepping up to the mark,” said Williams. “I have trained with Rhys and played against him and I know what a handful he is.

“He will have two experienced guys next to him in Matthew Rees and Gethin Jenkins so there are no qualms whatsoever that our front row can hold up their front row.”

Italy gave England a tough examination in Rome eight days ago and may well have beaten the World Cup finalists had their lineout not malfunctioned at crucial moments.

Gatland recognised Wales’ scrummaging deficiencies against the Springboks and he has been putting Thomas, the Newport Gwent Dragons tight-head, and Jenkins through some tough pre-match preparations.

It was one of the reasons Gatland decided to break with tradition and name his side to face the Italians 11 days before the match.

“It’s pretty important when you’re a tight-head prop that you can scrummage. I think for both Rhys and Gethin it’s an area that they have to focus on,” said Gatland.

“They both played against South Africa and the scrum was under the pump in that game. For a prop, the number one job is the set-piece - scrums, lifting at line-outs, defending and hitting rucks. Everything else is a bonus.

“For Rhys, he gets a chance to go out and perform and show that he is a contender going forward.”

Gatland’s decision to make six changes for the Italy game is founded on the theory that fierce competition for places can drive forward Wales’ development.

There is now a real edge to training and it is not unusual for that intensity to boil over and for tempers to fray - but for Williams that is a welcome sight.

It tells him Wales are moving in the right direction again following their World Cup disappointment.

“If I had known how tough the training would have been I might have had second thoughts about coming out of retirement,” Williams joked.

“It has definitely been a step up to anything I have ever experienced before.  The intensity does spill over - but if it doesn’t, then that is when you start to worry. All good sides have that.

“The sessions are shorter now but the intensity is unbelievable. You can’t cruise through a session. In the past maybe we have been guilty of being able to cruise through sessions because they have gone on so long.

“Now, there is no holding back, no half-measures. You come off after some sessions and feel like you have played a game, they are that tough."