SCOTT Williams says the threat of making defence coach Shaun Edwards' wall of shame will ensure standards don't slip in Wales' World Cup opener against minnows Uruguay.

Wales kick off the tournament against the Pool A whipping boys in Cardiff on Sunday and it promises to be a one-sided romp.

Centre Williams will hope to add to the nine tries that he has scored for his country but he also knows that he needs to avoid the ire of defensive drill sergeant Edwards.

"You don't want to be the one up on the board on Monday morning for a defensive error or you are going to have Shaun on you back for sure," said the Scarlets man.

"We have to keep our concentration for the full 80 minutes, our line-speed up and our discipline in defence.

"It's the little things that make a difference. When you are blowing the first thing that goes is your concentration. We have to make sure we are talking.

"We will know if we have made some errors on Monday morning. Shaun isn't scared of embarrassing anyone, which it good because it keeps you on your toes.

"I think everyone has been on the wall of shame. We are only human. I think everyone has been on it at some point, some more than others because no-one is the perfect player.

"Shaun wants to improve us and his way of helping us is by embarrassing us!"

Wales will spend most of Sunday's encounter with ball in hand and the aim will be to rack up the points in case a tie-breaker is needed in the group of death with England, Australia and Fiji.

Williams is hoping to channel the spirit of Super Saturday when they set the bar high by thrashing Italy in Rome, forcing Ireland and England to be at their best in the title race.

"It will probably be like our final game of the Six Nations," he said. "The most important thing is we put a performance in that gives us something to build on.

"We haven't spoken about any points score. We have to make sure we are on our game to get the performance we want. We have just got to make sure we do the basics well and keep the errors down.

"It is going to be a massive occasion for Uruguay to play in one of the best stadiums in the world – they will be ready to go."

- Edwards was full of praise for how Williams has coped with the move to outside centre.

The 24-year-old plays 12 for the Scarlets but is set to shift out for the big group games to be Jamie Roberts' partner.

"Scott has improved," said Edwards. "Certain aspects of his tackling, we broke it all the way down.

"He knew he had to work hard on his defence because, naturally, he's a good attacking player. He knew he had to step up a little bit with his defence, and I think he's steadily getting there.

"I am pleased with his progress. He's not the finished article yet but there's been a 20 per cent improvement."