Given that we'll probably only see half an hour of play in today and tomorrow's evening sessions, if I was Pat Cummins, I'd be wanting to be bowling not long before tea.

That would give the Australians about three, three and a half sessions to take ten wickets.

The Aussies lead by 280 right now, so I reckon they'll be looking to be around 350-380 in front by then.

Either way, we're set for some fireworks after lunch.

A mixed session with Australia losing four wickets, but also going at almost five an over.

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They lead by 280 so can bat for an hour, maybe a little longer after lunch before declaring with a 350-run lead.

At least, I think that will be the plan, but the South African bowlers will have a bit to say about that. Can they cause a collapse and keep the target within reason?

We'll find out a little later.

How kind of him.

What a shot! Harmer throws it miles down the leg side and Renshaw somehow manufactures a reverse sweep through cover for four.

Harmer is over the wicket, so Renshaw is padding up and just keeping them out here.

He looks to go the reverse sweep again, but pulls out as the line or speed isn't quite right for him.

He finds the single to cover more conventionally. So Alex Carey will face the last ball before lunch after a long readjustment of the field.

BEATEN! What a ball to beat the outside edge to end the session.

The umpires are having a look at a potential stumping, but Carey never lifted his foot.

Nortje starts by firing in a yorker that Carey digs out.

The way he bats with his hands away from his body, Carey always looks a threat of nicking off or chopping on to pace. If Nortje can stay in that fifth stump area, he will always be in the game.

Carey manages to find a single with a little dink to the vacant point region.

And Renshaw finds the space too as he jumps and clips a shortish ball off his hip to deep fine leg.

Renshaw is almost burned by Alex Carey! Renshaw clips to mid-on and calls "noYeah yeah yeah", taking off for a single before being sent back by Carey. He gets back comfortably, but there was probably a single in that.

Harmer is keeping these batters, both excellent players of spin honest. Just two singles from the over.

And Alex Carey clips off his hip to start the over with a single.

Nortje's first to Renshaw is more hostile, short and down leg. The bouncers ruffled Renshaw a little in the first dig, so this isn't a bad tactic.

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Renshaw pushes into the deep on the off side and thinks about two but decides against it as Keshav Maharaj comes in off the rope.

Gorgeous from Nortje as he seams across Alex Carey to beat the outside edge. What a ball to the new batter.

The off spinner is looking really tough to play out there right now. Nathan Lyon is licking his lips, but Australia's lead is still only 267 runs, so the batters still have some work to do.

A couple more singles to the tally, but the decisive boundaries have dried up.

No slips in place for Keshav Maharaj an over after getting a wicket. A fascinating decision.

Almost bowled him! Renshaw goes for the lap sweep and gets barely anything on it to the point it almost rolls back onto the stumps. Renshaw ends up diving to put his body between the ball and the pegs.

Both these batters will sweep and reverse sweep all the live long day.

Just three runs off the over though.

Quick, but not blazing, runs needed. Matt Renshaw and Alex Carey at the crease. They just need to treat this like an ODI. Fortunately for Australia, these are two good practitioners of that sort of dig.

Renshaw is just calming things down as Simon Harmer continues.

Renshaw sees out the first five of a handy Harmer over before clipping a single to the leg side to retain the strike.

It's back-to-back 37s for Marnus Labuschagne as he backs away to try and clips through cover, but only chips a catch to Temba Bavuma at wide mid-off.

He looked so good today, but again he falls short of a truly significant score.

Credit to Keshav Maharaj for finding a little extra turn and bounce to find the outside half of the bat, but Labuschagne is filthy with himself.

Marnus Labuschagne steps back and punches to deep cover for another single.

Four. Renshaw is going to the reverse sweep well a lot here, but he's not timing it as sweetly as he was in the first innings. He gets enough on this one to claim another boundary though, almost directly behind him.

Another one! This time he smokes it and gets the boundary in front of square leg.

A little too short to start by Harmer and Labuschagne works off his thigh for a single. All this strike rotation is exhausting for a fielding side, especially when it's a righty-lefty partnership.

An excellent delivery from Harmer extracts some turn and bounce, and finds the edge of Renshaw. But Labuschagne at the other end shows good awareness to sprint from for a single.

A more decisive stroke from Labuschagne through cover (he's getting into his work here) and that's another single as the deep sweepers cut it off.

Renshaw is trying to work the reverse sweep again but miscues.

He shapes again and Maharaj drops it short, so Renshaw just lets it go over his shoulder and it races away for four byes.

Renshaw is spamming that shot and eventually gets the single.

Another quick single, this time with more surety, as Labuschagne drops behind point and immediately calls Renshaw through. Good hustle by the Bulls.

Marnus Labuschagne is trying to slap across the line and is struggling to find the middle of the bat.

RUN-OUT CHANCE! Labuschagne clips to the leg side and takes off, stutters, then calls Renshaw through. Temba Bavuma is a danger in the field as he gathers at mid-wicket, but a tiny fumble as he tries to throw allows Renshaw to make his ground. No fumble and I reckon Renshaw is out by some distance.

The singles keep on coming. This is all the Aussies need to do. Work the singles and punish the occasional loose one.

Four! Maharaj resumes and Matt Renshaw goes the sweep, getting an edge over the shoulder of wicketkeeper Kyle Verreynne.

Renshaw is going for the conventional sweep here, but there's a fielder in the deep there to cut it off.

Labuschagne edges wide of slip and pinches a single as he settles in with his Queensland teammate.

And there's the reverse sweep from Renshaw, played safely and expertly for another single.

Labuschagne ends another expensive Maharaj over with a single to long-off.

Steve Smith is out for 27 as he tries to send Simon Harmer into the stands again but can't get it as cleanly this time. It goes low and hard straight at Marco Jansen, who parries his first grab above his head up in the air before regathering the ricochet.

If Temba Bavuma had been there, it might have been another six.

That brings to the crease Matt Renshaw, fresh off his 190 on day two. So confidence should be sky high.

Smith has the strike and gives it up with a lovely clip wide of mid-on for a single.

Struggling to get Maharaj away at the moment like they did in the first innings.

Four! The Marnus Labuschagne cover drive is in full effect as he whips along the grass to the rope. Very Virat Kohli that shot.

Harmer mixing up his speeds well and Labuschagne defends a glacial one from the offie.

A big LBW shout! Marnus Labuschagne is hit in front and the umpire says not out, but South Africa reviews.

The angle shouldn't work for an off-spinner, but Harmer didn't turn this one much. Still, it would take some almighty drift down the line of the stumps to make this one out.

NOT OUT. The delivery is missing leg stump by quite some distance. That's a bad review by South Africa.