Luck deserted Australia in their desperate bid to salvage the second Test with South Africa snaring the vital wicket of David Warner in unfortunate circumstances in Hobart on Monday.

Warner, who was seeking redemption after his reckless dismissal in the opening over of the first innings, lost his wicket while at the forefront of Australia's fightback.

At stumps on the third day the home side were hanging in at 121 for two, still 120 runs behind the Proteas, who have been in control of the Test since routing Australia for 85 on Saturday.

Usman Khawaja was unbeaten on 56 with skipper Steve Smith not out 18.

Warner flung his head back in despair when a ball from Kyle Abbott hit his hip and ricocheted off an elbow onto his stumps when he was on 45.

It gave the Proteas a huge fillip after Warner and Khawaja had recovered the innings with a 79-run stand after the loss of Joe Burns in the first over.

Burns was caught behind tickling at one wide down the leg-side from Abbott.

South Africa earlier extended their first innings lead to 241 before they were all out for 326 with Quinton de Kock plundering a century and Josh Hazlewood finishing with six for 89.

Hazlewood captured three of the last four wickets to fall after lunch for his second-best haul after his six for 70 against New Zealand in Adelaide last year to take his tally to 88 Test wickets.

Shortly after lunch, Tembo Bavuma was surprised by a rearing delivery to spoon an easy catch to Nathan Lyon at point and give Joe Mennie his first Test wicket for 74.

After Sunday's second day was washed out, the Australians chased early wickets but de Kock and Bavuma batted South Africa into a position of strength with a century stand.

The swashbuckling wicketkeeper was bowled by Hazlewood just before lunch for 104 off 143 balls with 17 boundaries.

His stand of 144 with Bavuma was the highest by a visiting team in Hobart for the sixth wicket.

De Kock became only the fourth South African to register 50 or more in five consecutive Tests after he swept spinner Nathan Lyon for four over wide mid-on.

SCORES IN BRIEF

AUSTRALIA: 85 (Smith 48; Philander 5-21) and 121-2 in 36 over (Warner 45, Khawaja 56 not out; Abbott 2-55)

SOUTH AFRICA: First innings 326 (De Kock 104, Bavuma 74, Amla 47; Hazlewood 6-89, Starc 3-79)