Kyle Abbott came into the Test series unsure if he was among his team's top four pace bowlers, yet finished as man-of-the-match in South Africa's innings demolition of Australia in Hobart on Tuesday.

The 29-year-old seamer from Zululand cracked open the porous Australian batting with the figures of six wickets for 77 to finish with nine wickets for the match.

It was Abbott's probing swing that undid the brittle batting order, engineering another collapse of eight for 32 in 116 balls and plunging Australian cricket deeper into a crisis of confidence.

Abbott, who was called into the Hobart Test as a replacement for senior strike bowler Dale Steyn, who suffered a shoulder injury in the first Perth Test, revelled on the receptive Bellerive pitch.

"We never thought we would get close to bowling them out in a session," Abbott said.

"From the start of the Test we spoke about winning in the last session, taking it deep and being patient, so when things speed up like that, it is rewarding.

"But we bowled really well last evening and that was our investment session for this morning."

Abbott was part of a potent three-man pace attack along with Vernon Philander and young gun Kagiso Rabada, who played his part by taking the other four wickets in Australia's second innings.

"We know the confidence in the Australian middle-order is a bit low to put in a performance there," he said.

"A bit of momentum in our favour, knowing that when we've had them three or four down, we've rolled through them."

Abbott said the South African team worked on becoming more ruthless.

"That's what we've wanted to really improve on in this series, and really fighting as hard as we can and being ruthless and creating pressure from both ends with the ball," he said.

"That's what Test cricket is about, who can hold the pressure the longest and being ruthless and never being happy with what you've done and wanting more.

"We are in a good space and I think our cricket is proving that."