It's a given that Saturday's Tri-Nations Test between the Springboks and the All Blacks will be an intensely physical affair. Both teams know that, with the visitors more acutely aware of it.

Among them, Andrew Mehrtens has not had the best of fortunes at Ellis Park, a cauldron where the Boks seem to grow a few more inches.

The All Black pivot was quite frank on the eve of this crucial match. "Every Test is tough but Ellis Park seems to be a wee bit tougher because the anger and passion of the fans is a little more intense than anywhere else, and the crowd is so close to the ground."

The Boks have their backs to the wall and that makes them even more dangerous. "South Africa is the most physical test you play," admits Mehrtens.

"There is always a lot of bash. It requires a different kind of preparation, especially for me. You know you are going to have to fight. You get stuck in every game but against SA you know they are going to fight back just as hard as you are.

"That is the difference between SA and Australia. Australia is not intimidated by the All Blacks, but I think physically you can get into them more whereas the Boks relish the physical challenge. They thrive on it if you try and get into their faces. In the last Test between SA and Australia, when the Boks started flying up and knocking them over, the passes to Larkham started going awry."

Mehrtens believes that the game's greatest rivalry is based on the physical nature of the matches. "In the past New Zealand teams have been hard-nosed and brutal but they found that the Springboks were the only team they could not intimidate. They found the Boks were prepared return the medicine."

Naturally, Mehrtens disagrees. He chooses his words carefully when reflecting on a Springbok backline that has not scored a try in two-and-a-half test matches.

"We see the potential of what the Boks can do. We know the players from the Super 12. In our preparations we focus not so much on how they have been playing recently but rather on what we know they are capable of producing."

The pressure on the Boks to reverse their slide reminds Mehrtens of the All Black nightmare of 1998 when they lost five in a row.

"It's a very difficult position to be in. They are trying new stuff, and people are questioning what they are doing. The Boks are probably trying too hard.

"When you are trying to prove people wrong, it is so easy to get into the wrong mindset. It's counter-productive to be telling yourself that you have to do this and you have to do that."