Bloemfontein, the host city for the tour opener, is 4,665 feet above sea level and will present a major test of Wales' fitness levels.

Jones, who has been recalled to the back row, started the 53-18 defeat by the Springboks in Pretoria in 2004 and knows the toll playing at altitude can take.

Wales leave their Cape Town training camp on Friday when they head for Bloemfontein with the first Test staged at Vodacom Park 24 hours later.

"We have great professionals on the fitness side and they've done their research," said Llanelli forward Jones.

"We'll be travelling up late. On a two-Test tour like this we've been told that's the best way to go about it.

"When I was here in 2004 it was a frantic game. I did notice the difference playing at altitude.

"Having that experience under my belt for Saturday's game will certainly help."

Injury has robbed Wales of key players such as Gavin Henson, Martyn Williams and Mike Phillips for the tour but the European champions still possess enough match-winners to cause an upset.

Chief among them is electric winger Shane Williams, Wales' record try scorer and this season's player of the RBS 6 Nations, whose enduring brilliance is crucial to his side's hopes against South Africa.

Williams' dazzling footwork has made him a lethal finisher and a favourite with the fans, earning a glowing tribute from Wales team-mate Alun-Wyn Jones.

"Over the past few years Shane has been a talisman for Welsh rugby," said Jones, who starts at lock against the Springboks.

"He's a bit like a fine wine as well - the older he's got, the better he's got.

"He was always a talent but things turned for him at the 2003 World Cup and since then he has never looked back. It's been a phenomenal experience playing with him.

"Coming into the Ospreys set-up and then the Wales set-up as a young player, when I won my first cap in Argentina in the same team as Shane was a bit unbelievable.

"You aspire to play for your country but also be associated with players like Shane.

"Whatever stadium he plays at there is a gasp whenever he gets the ball.

"He can be quite frustrating in training when you are doing one-on-one drills - but he is the same when we do contact.

"He has great agility. You can't use words to describe some of the things he does.

"When you watch him play it is like there aren't any white lines. He seems to be able to run over the lines without touching them."