QUALIFIED doctor Jamie Roberts will put himself through physical torture once more tomorrow in an attempt to end Wales' prolonged mental anguish against the southern hemisphere superpowers.

Just a week after standing toe-to-toe with world champions New Zealand for almost 70 minutes of an encounter that was underpinned by brutal intensity, Wales now face renowned pain merchants South Africa.

While the All Blacks' all-singing, all-dancing game has elevated them to unprecedented levels of brilliance, South Africa have remained among world rugby's heavyweight top three nations through frequent reminders that their physical power can be overwhelming.

Twelve of the Wales team that started against New Zealand are back for more this weekend, and powerhouse centre Roberts – hardly a lightweight at 6ft 4in and more than 17 stone – has dusted himself down, ready to go again.

"It has taken about four or five days to recover. It was car-crash stuff at the weekend," he said.

"I take anti-inflammatory medication before most games now just to reduce the swelling in the knees and ankles, and so forth.

"It kind of numbs most things during the game, and when the effect wears off ... usually the day after the game you feel alright, but it's after that. Monday and Tuesday are pretty horrific.

"It's a bit different when you are 21, compared to 28. When you are a bit younger you could probably run a marathon the day after a rugby game, but any player will tell you the same.

"That's why we do recovery sessions. We trust the medics, the conditioning coaches and the recovery process."

Asked if he worried about his body and any long-term impact, Roberts added: "Sometimes. I have to enjoy the present – that is what it's about. I will worry about that when my career finishes.”

Statistics are also hurting Wales at the moment – never more so than when it comes to beating South Africa, New Zealand or Australia.

It has not happened since November 2008, when the Wallabies lost 21-18 in Cardiff, and the overall picture under Wales head coach Warren Gatland is a bleak one against the so-called big three - played 27, lost 26.

"I think this weekend is all about mindset. The hard work is done, the boys are used to playing at that intensity now and the structures are in place," Roberts said.

"Against a team like the Springboks you have to front-up against these guys.

"We are all completely gutted about last Saturday, but it's also a bit of a wake-up call to the level that we need to get to.

“You can do all the training you want, but unless you test yourself against the best, that's why I like playing the best.

"It's like in any walk of life. When you come up against the best in any job, you know you have to raise your game.

"It is the last game of the season for South Africa and they will not want to go three or four months away from rugby having lost the last game of their tour. It's going to be a brutal Test match."

Less than a year out from the World Cup, Gatland believes Wales are ahead of schedule compared to where they were at the corresponding period before World Cup 2011, a tournament when Roberts and company secured semi-final status.

And while results might suggest otherwise, Roberts has no doubt that continued exposure to the southern hemisphere elite is critical towards Wales arriving at next year's global spectacular in impressive shape for pool stage challenges that include former world champions England and Australia.

"People are always very quick to look at results," he added. "We would love to have beaten Australia or New Zealand, or both, this month.

"But when you look at the process building towards the World Cup, to test ourselves against the best three teams in the world about 10 months before the World Cup is of huge learning value to us.

"As a player, even though you lose, you learn and gain far more than if you are winning 50-0 against a tier two nation. Wales opted to play against the big three for a reason. Hopefully, this weekend, we get a win.

"The players still feel like we're learning. I learnt a hell of a lot last weekend.

"Rugby is a simple game. Look at the All Blacks - they do the simple things well, they don't panic, they are relaxed and composed."