Durban - Australian opening batsman Cameron Bancroft said on Saturday that South Africa's batsmen will face a major challenge in the fourth innings of the first Test at Kingsmead.
Although South Africa fought back to reduce Australia to 213 for nine in their second innings at the end of the third day, the Australians hold an overall lead of 402.
Bancroft, who top-scored with 53, said conditions would be difficult for the South Africans when they eventually start to bat.
"The ball is starting to reverse-swing a lot more," said Bancroft.
"For new batters starting their innings that's very, very difficult. The wicket has just slowly deteriorated. There are a lot more bare patches and the ball's reverse-swinging earlier and earlier because of that abrasiveness."
Adding to what is already shaping as a massive task for the hosts, opening batsman Dean Elgar suffered a dislocated right little finger when he held a catch at cover off a ferocious drive by Mitchell Starc off Morne Morkel late in the day.
Elgar left the field and a team spokesperson said the finger had been put back in place and Elgar would be able to bat.
Bancroft and David Warner got Australia off to a bright start against the new ball when they started the second innings with the considerable cushion of a first innings lead of 189. They put on 56 in 13 overs before Warner was caught at mid-on for 28.
The scoring remained brisk as Australia reached 112 for three at lunch. But it dried up after lunch, however, and Australia lost six more wickets while eking out another 101 runs in 44.4 overs before the umpires took the players off the field.
Bancroft made his first fifty since he scored 82 not out on debut against England in Brisbane in November.
"It's pretty important," he said.
"Cricket is one of those games where it can be not very rewarding at times. In my own game I feel I have been improving, doing a lot of very good things and sometimes they don't come out and be recognised in the middle."
Bancroft was struck on the body by a hostile lifting delivery from Morkel in a testing first over. But he went on bat impressively, scoring his runs off 83 balls with ten fours before he was stumped off left-arm spinner Keshav Maharaj.
South African assistant coach Malibongwe Maketa said South Africa's bowlers had shown improvement on their first innings performance.
"We did feel we gave away way too many boundaries," he said.
Maketa acknowledged that South Africa were in a difficult position after a poor batting effort when they were bowled out for 162 in their first innings.
"A few guys probably came in not having hit enough but they have played a lot of cricket and they know what is required to do well at this level. We've got faith that we can still be a factor in the game," he said.
Kagiso Rabada bowled with pace and hostility and was unlucky not to claim more than the two wickets he took for 28 runs.
Bancroft and Warner attacked Maharaj when he started to bowl on Saturday, scoring 20 runs off his first two overs. But Maharaj settled down and again bowled the most overs for South Africa, following up a five-wicket haul in the first innings by taking three for 93 in 28 overs.
Morkel, who did not bowl between lunch and tea after bowling poorly in the morning, came back strongly in late afternoon and finished with three for 42.