SOUTH AFRICA are Richie McCaw's toughest rivals in terms of physicality and his results against them, so naturally the New Zealand captain cannot wait to get stuck into them yet again in today's World Cup semi-final.

McCaw will face the Springboks for the 26th time. They have notched up six wins over the All Blacks in the previous 25 games and are, statistically, the most successful of his personal international opponents.

They are probably also the best team at inflicting physical damage on flankers who play on the edge of the laws, so McCaw knows exactly what to expect.

"There is a massive intensity between the teams and tomorrow will probably be another step up," he said after a run around Twickenham yesterday. "The matches against the Springboks are some of the toughest you ever play. It will probably be another brutal game but they are the games I love. Being in that environment with that sort of opponent in that intensity is why you play. Picking up the odd scar is part and parcel of it and if we do the job I'll take any extra scar that comes along."

McCaw won the first of his 146 caps 14 years ago and though he has obviously developed hugely as a player and leader, he said it was also helpful to try to recall his attitude when he first broke into the team.

"I sometimes wonder how I managed to function at all back then but you do it on energy and excitement I guess," he said. "I think when I made my debut I was just running on pure instinct, and I didn't want to stuff it up. I think as you gain the experience, and with the captaincy role, you realise you have got more than just playing yourself, it is about helping the men around you. I think that is a good reminder that you probably overthink the game at times when you have been around a while. So if you play with a bit of instinct, using the knowledge you have picked up, you can do a pretty good job."

He can certainly do that. Four years ago to the day, playing on virtually one leg, McCaw dragged New Zealand past France to finally reclaim the World Cup after a catalogue of painful near-misses.

They won that nervous finale 8-7 and though a higher-scoring affair is likely on Saturday, McCaw said the winner would still be the side who get the basics right under the most intense pressure.

"What counts is being able to do the things that mean you can get across the advantage line," he said. "The subtleties of the guys who are able to put guys in space can look flash, but it is often the result of getting the basics right."

Pressed on his favourite memory from his quarter-century of games against South Africa, McCaw ran through his mental box set and settled on an encounter from seven years ago.

South Africa had just won in Dunedin for the first time and were on a roll but found themselves shut out on home soil in a 19-0 reverse.

"The one that sticks to mind is the one we played in Cape Town in 2008 when we managed to keep the Boks scoreless," he said.

"That was a pretty cool performance. We'd had a rough start to that year. I wouldn't mind if you asked me that question on Monday, and I would say 'Saturday'."