Williams and company have swept aside all their RBS 6 Nations rivals twice in four seasons, winning Grand Slam titles on each occasion.

But the record against rugby union’s southern hemisphere super-powers South Africa, New Zealand and Australia is abysmal.

Wales have beaten the Springboks once in 102 years, while they last defeated the All Blacks 55 years ago and can only claim one win in 20 years against Australia.

But after landing last season’s RBS 6 Nations title, Williams accepts that public expectation has soared.

He said: “Last year going into the Six Nations, there were no expectations, especially after being knocked out of the World Cup.

“People are looking now not just for us to compete, but to go up a notch and take a big scalp.

“We have got to try to beat one of the three big southern hemisphere teams now so that we can take the next step.

“There is going to be a great atmosphere, and everyone is really excited about it. This will be a proper measure of where northern hemisphere rugby is.”

The Springboks, 2007 World champions, include eight of the team that beat England to lift the Webb-Ellis trophy for their clash with the Dragons this weekend.

And after what should be a routine appointment with Canada in Cardiff next Friday night, New Zealand and Australia rumble into the Welsh capital.

Williams added: “Wherever they play in the world, South Africa always present a big physical challenge.

“It is the biggest you will ever face, so it’s up to us to be smart and not give them too much ball.

“We are familiar with them, and we want to go out and prove we are better than we showed in the first Test there in the summer (Wales were beaten 43-17 in Bloemfontein).

“I didn’t go on tour because of my knee, but that first Test is brought up often by the boys, though we managed to turn it around for the second Test.”

Wales led by a point at one stage of the second-half in Pretoria before South Africa ultimately prevailed 37-21.

Head coach Warren Gatland makes eight changes from that game, including recalls for the likes of Grand Slam stars Williams, centre Gavin Henson and full-back Lee Byrne, who all missed the tour through injury.

But there are also two Test debutants in the form of 19-year-old Cardiff Blues wing Leigh Halfpenny - he is set to line up opposite Springboks try machine Bryan Habana - and Blues number eight Andy Powell - plus a new midfield combination in Henson and Jamie Roberts.

It will take a Herculean effort for Wales to even go close, yet if Gatland’s steely determination is mirrored by his players, then do not rule out an upset.

“While we are incredibly proud of being Six Nations champions and achieving the Grand Slam, we also want to compare ourselves to the best,” said Wales defence coach Shaun Edwards.

“We are expecting South Africa to create the ultimate challenge.

“But Warren is an incredibly competitive person, and he wants to compare his team against the Tri-Nations sides.”