The hosts are attempting to respond after suffering a 214-run defeat in Durban, but their progress has been hampered by persistent rain, with only 43 overs bowled across the first two days.
Australia paceman Scott Boland has exploited the conditions effectively, claiming four wickets for 31 runs to leave South Africa struggling at 97/5. His victims included Aiden Markram, dismissed for 11, and David Bedingham, who edged behind to Alex Carey.
Petersen believes captain Temba Bavuma has demonstrated the composure required, urging the middle and lower order to follow suit and build a competitive total.
"I think it's going to be tough because, obviously, every time you come here, there's moisture in the surface. It's almost like the grass stands up. And that's what the bowlers want, someone like Scott Boland, who can be compared to Vernon Philander," Petersen told IOL.
"They want something where they can pitch the ball, get the seam to scramble a bit and go both ways. So I think it's going to be tough.
"What I've seen in recent seasons is that the guys are actually reaching for it, whereas you have to go in and play the ball late. But it's difficult.
"It takes a while for you to really get used to the tempo and all of that, and when you feel like you can do so early on, it's going to be a real struggle.
"If you look at the two teams, Australia and South Africa, South Africa will have two choices… Now the question is, how are you going to play? Are you going to try and make something happen? It's hard to say."
Proteas captain Temba Bavuma struck his fifth Test century, and the best of his career, as the hosts dominated Australia on the third day of the second Test at St George's Park in Gqeberha.
The Proteas lost another three wickets but captain Temba Bavuma was standing firm as the hosts were 97-5 at the end of a shortened second day of the second Test against Australia at St George's Park.
South Africa suffered two wickets after lunch to end day one on 20/2 after only 12.2 overs in a rain affected second Test at St. George's Park on Sunday.
David Bedingham insists the Proteas batting unit need to show patience and endurance against Australia's world-class bowling attack as the teams gear up for the second Test in Gqeberha on Sunday.
