Head's unbeaten 87 leaves Australia 170 behind with a day to save the Gqeberha Test

Australia were made to follow on at St George's Park and closed the fourth day on 156 for 4, still 170 runs behind South Africa with six wickets left to save the Test

Travis Head was unbeaten on 87 from 138 balls at stumps, nine boundaries among them, and is the one Australian batter to have looked settled in a match where the visitors have been taken apart twice in two days.

Australia were bowled out for 99 in 42.3 overs in the morning session, a collapse that handed South Africa a first-innings lead of 326 and left Temba Bavuma an easy decision at the follow-on.

South Africa need six wickets on the final day to level the series. Australia need to bat through it, or at least long enough to make their hosts bat again.

Jansen's morning tears through the order

Marco Jansen had nightwatchman Scott Boland caught behind off the first ball of the day and finished with 5-33, the best figures of the match.

Head went for 14 to leave Australia 22 for 3, and Jansen later removed Matt Renshaw and Alex Carey within three deliveries before having Beau Webster caught by Aiden Markram.

Steve Smith top-scored with 28 from 88 balls before Wiaan Mulder bowled him, passing 11,000 Test runs along the way to become the third Australian to the mark after Ricky Ponting and Allan Border.

Mulder finished with 2-14 and Kagiso Rabada 2-33. The total of 99 is Australia's fourth-lowest against South Africa.

Head and Labuschagne dig in

Rabada removed Nic Maddinson for 8 in the second innings, a second cheap dismissal in the match for the opener, and Australia were one down with the arrears barely dented.

Head and Marnus Labuschagne then put on 92 for the second wicket, the only substantial partnership Australia have managed at the ground.

Labuschagne made 39 before going after Simon Harmer and finding Jansen running back from mid-on, the ball held up long enough in a stiff Gqeberha breeze for the fielder to get under it.

Rabada and Harmer keep chipping away

Rabada bowled Renshaw for 11, a sobering end for the batter who was named player of the match in Australia's win in the first Test.

Harmer then trapped Webster lbw for 8, the off-spinner's second wicket in an 18-over shift that cost 47.

Boland came back in as nightwatchman and was 2 not out at the close, leaving Head to shepherd a tail that has offered little all match.

Nortje's groin forces Bavuma to improvise

Anrich Nortje bowled only 3.3 overs in the second innings before pulling up and clutching his right leg.

Cricket South Africa said initial assessments showed no severe tear, and the fast bowler took no further part in the match as a precaution.

That left Bavuma rotating Rabada, Jansen, Mulder and Harmer in short spells through the afternoon, a workload that matters with a full day's bowling still to come.

What the final day is worth

South Africa's 425 for 9 declared was built on Bavuma's career-best 179, with Jansen making 85 and Harmer 82 from the lower order.

Australia lead the series after winning the first Test by 214 runs, so a South African win here squares it and a draw leaves the tourists in front.

Australia chose to bowl after winning the toss, a decision that has cost them two batting collapses and the match situation they now face.

Scorecard: South Africa 425 for 9 declared (Bavuma 179, Jansen 85, Harmer 82); Australia 99 (Smith 28, Jansen 5-33) and 156 for 4 following on (Head 87*, Labuschagne 39), trail by 170 runs

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