Former South Africa captain Gary Teichmann has warned the British and Irish Lions will have to improve by at least 30% if they are to level the Test series on Saturday.
Teichmann knows from his experiences with the Springboks in 1997 what pressure the Lions are under as they head into the second Test trailing the series 1-0.
The Lions struggled to contend with the Springboks' scrummaging and mauling power as they fell 26-7 down within 50 minutes last weekend before staging a late comeback.
Teichmann believes the key to Saturday's showdown at Loftus Versfeld will again be the set piece and the rolling maul - and whether the Lions can counter South Africa's drive and use it as a weapon themselves.
"I think the Springboks will be a good 30% better this weekend," he said.
"The Lions have got to be competitive in their scrums but my biggest concern for them is defending the rolling maul. That will be a key area.
"The altitude means the ball travels a lot further so you will be looking to create more opportunities to drive from the lineout.
"They will also have to be clinical when they get their opportunities. I don't think the Lions will get the same number of try-scoring opportunities as last week.
"It will be a tight game with a lot of kicking for territory."
The Lions announce their team later today and it is widely predicted that hooker Matthew Rees and prop Adam Jones will come into the front row in a bid to counter the Springbok scrummaging power.
Teichmann would consider just one other key change to the starting line-up - Ronan O'Gara for Stephen Jones at fly-half - but he believes the Lions must be bold on the bench and fill it with match-winners like Shane Williams and James Hook.
"The Lions have to look at the front row but I don't think there will be too many changes. I think they might give O'Gara a go, but Jones' defence against Schalk Burger could swing it back his way," he said.
"I don't think they will make changes in the lock or back row and they like the bulk of Ugo Monye.
"But I always believe the guys on the bench have to make a difference. I don't believe they should have O'Gara and Jones in the squad.
"I would prefer Hook. He was playing really nicely until he got injured and although Shane Williams has not had the best tour he is a match-winner."