That setback, coupled with the pain of defeat on home soil against England last weekend, will leave Andy Robinson's side desperate to kick start their RBS 6 Nations campaign.

That man Williams was also to the fore last season as Wales got the edge over Robinson's troops at Murrayfield, scoring two tries in a 24-6 win.

The diminutive winger has now hung up his international boots but any thoughts of his exit giving some respite to the Scottish defence were spectacularly quashed by Wales' performance in their 23-21 win over Ireland last weekend.

Try-scorer George North took Williams No. 11 jersey and provided a performance of power and poise that defied his tender years while another member of the backline, Jonathan Davies, crossed twice.

But despite the standout performance of the backline it is events in the pack that have left Warren Gatland purring with delight in the build-up.

Influential prop Gethin Jenkins returns to the starting line-up after recovering from a knee injury while Dan Lydiate returns to the back row in place of Ryan Jones who covers in the second row for the suspended Bradley Davies.

And Gatland admitted he is only too pleased to welcome the pair into the fold.

"Gethin brings a wealth of experience to the team, which is the main reason we have brought him in for Rhys, who is unlucky to miss out with Paul James covering both sides of the scrum from the bench," said Gatland.

"Dan's return from injury is timely and Ryan's versatility allows us to cover for Bradley with minimum disruption, with Lou Reed also giving us an extra option from the bench.

"We cannot afford to underestimate Scotland, the amount of possession and territory they had against England last weekend meant that they should have won the game and they will come to the Millennium Stadium buoyed by that knowledge."

While Wales have seen their numbers bolstered, for Scotland the build up has been disrupted by some absentees.

After seeing his kick charged down by Charlie Hodgson for the decisive score as Scotland lost to England last week fly-half Dan Parks has called time on his international career.

He will be replaced in the No. 10 jersey by Greig Laidlaw while the only other change is also enforced with Geoff Cross replacing Euan Murray - who doesn't play on Sunday's due to his religious beliefs - at tight-head prop.

Despite making just two changes to the starting line-up Robinson has rung the changes among the replacements.

Prop Ed Kalman, 20-year-old fly-half Duncan Weir and 19-year-old full-back Stuart Hogg are all in line to make their debuts.

And Robinson admitted the time was right for Parks to take his leave and Laidlaw to take over at fly-half.

"Congratulations to Greig on his first start," said Robinson. "He is a gifted footballer who is acclimatising very well to the differing demands of the stand-off position having spent most of his career at scrum-half.

"Having lost last weekend, I believe the time is right to move on and look to develop our emerging talent at stand-off.

"I've always stressed the importance of the A team and the part that both Duncan Weir and Stuart Hogg played in the game at Netherdale last week is another reason for my continued excitement and belief in Scottish rugby."