Mitchell Starc blitzed the Proteas tail late on day one to give his batting line-up the perfect chance to shine on day two.
But can they make it count?
Follow the action with our live blog.
Key Events
Keeper up
Rickleton is keeping up to Mulder and it has reined in the Aussies just a touch.
He bowled a strong maiden and Renshaw was just watching him extra close being pinned to the crease.
AUS 2-163
Another one
Renshaw nabs his half century the very next ball and the Aussies are building nicely.
AUS 2-146
Half century!
Green reaches his half century and it’s a timely knock for Austalia.
He needs to make this start count now though.
AUS 2-145
Review
South Africa are excited after Harmer hit Renshaw’s back pad but the umpire was worried about height.
There was no bat involved and ball tracker lands on umpire’s call.
Renshaw escapes on 49!
AUS 2-144
Greeny!
Rabada went short and Green smacks it away to the fence for a maximum.
So the big South African doubled down and nearly did for the Aussie.
He went after it again and just got it over the head of deep square-leg.
He gets another six but risky.
He hits a third one much better into the empty space in front of square and get four.
He has now raced to 49 and is on track for a half century before Renshaw.
AUS 2-136
Quick!
Renshaw is calling through some drop and runs and Green needed every inch of his long stride to make it.
But it’s good batting from the Aussies who are ticking over well.
AUS 2-112
Rabada probing
The star Porteas quick finds an outside edge from Renshaw but his soft hands gets it straight to ground and it runs to the boundary.
Australia are into triple figures with Renshaw moving to 36 from 86.
AUS 2-104
Caught! Almost
Coetzee catches the outside edge of Green’s bat and third slip takes a catch.
The Aussie stands his ground and the umpire’s want the catch checked. The replay could have gone either way but the umpire believes the ball hit the ground as it went up into his hand.
The ball was full but Green didn’t get a full stride in.
Maiden
Coetzee gets us underway with six dot balls against Renshaw.
He is in the attack to go hard at Green with sort balls but Rabada is the danger man at the other end.
AUS 2-90
Back on
We are ready for the second session.
Big one for Green. Can he make a big score?
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