Great work from Marco Jansen and Simon Harmer to wrap a tourniquet around the South African batting line-up, because the Aussie bowlers were on a tear.

So the equation is simple. I won't back the last four South African wickets to put on enough to make Australia bat again, so it's a matter of them needing to survive a full day's play (weather permitting), and Australia taking 14 wickets.

The way this series has gone, you wouldn't bet against Australia.

We'll be back tomorrow for an inexplicably exciting conclusion to this series.

Can't wait!

Simon Harmer on strike. Short leg, catching mid-wicket, catching extra cover, a slip and a gully in place.

Harmer gets a short ball and pulls it away for a single. So Janse, who remember got a half century in the last Test, will face up.

He too gets off strike, leaving Harmer to face the penultimate ball of the day.

He defends well and Jansen wanted a tight single for some unknown reason. Harmer sends him back and reckons he can see out the last ball.

He's done it. Stumps!

Jansen drops to one knee as he leaves outside off. Bizarre, but whatever gets you through to stumps I suppose.

No shot offered and it finds the back pad, but not doing enough for LBW. Lucky he didn't get bowled as it went through his legs to be honest.

Half a shout for LBW to end Lyon's last over! Outside off. Marco Jansen just bought a two-storey walk-up on Struggle Street there.

He'll have two overs.

Harmer is happy to shoulder arms to anything not cannoning into middle.

Hazlewood spears one in and Harmer defends it off his stumps.

Really solid defence from the offie.

Four! Lovely stroke as Hazlewood tries the in-swinging full one, but Harmer clips off his toes like a right-handed Usman Khawaja.

No-one on the off side in front of the bat under the lid.

Jansen is defending this well as Lyon gets much straighter, bowling to this leg-side field.

He's almost chopped on! He tried to pull the bat away at the last second and toed it, but just over the stumps.

Four! No-one's in front of the bat, and Marco Jansen gets a good stride in and drives through mid-off. Bit of a half-volley from the skipper. Perhaps tiring a bit.

He's coming back around the wicket to Jansen. And he goes with the double-bluff yorker, but Jansen digs it out.

2-14 from six overs in this spell. Honestly, it felt better than that.

Credit to Marco Jansen for some proper driving.

Simon Harmer has 24 first-class fifties and two tons, but a high score of just 38 from his nine Tests so far.

The light is fading. Wouldn't be surprised if Australia was told to only bowl spinners.

Harmer is surrounded by four in-close fielders who won't shut up. Won't worry this experienced Essex lad.

Oh, that one really bounced up into the gloves as Harmer got forward. Lucky that didn't pop up.

Harmer's first ball is a tight leave.

And the next is almost straight to leg gully! So close.

Back to regulation stuff, just getting a ball to nip away and find the outside edge through to Steve Smith.

This is a truly great spell of fast bowling from the Australian skipper.

South Africa are 6-137 and out comes Simon Harmer.

He's sticking with the around-the-wicket angle to Verreynne, who pulls away for a single. Don't think Cummins will mind getting a shot at Jansen. He's a big target.

He's come back over the wicket. I, for one, feel much more comfortable watching this.

He still starts short, but Jansen can defend.

Jansen drives down the ground and Cummins thought he was in the game for a caught and bowled for a hot second, but not quite. Again, would've been one of the all-time greats.

Is there a temptation to go pace from both ends, or will they stick with pace from one end and spin from the other?

HUGE SHOUT FOR LBW! Jansen shouldered arms and almost tripped over as he padded up. He didn't want to know about it. He's given not out, but Australia reviews. I can't imagine this was spinning enough. Close though.

Oh it's umpire's call! Probably hitting off stump by about as much as the one that got rid of Sarel Erwee. The good news for Australia is they keep their review.

And he's almost snuck one past the inside edge to finish. Jansen looks in all sorts out there.

A short one stays low and that's not going to make life easy for Jansen.

Ouch! Jansen wears another bouncer on the chest from around the wicket.

And then he just manages to fend one away. Lucky not to go straight to a fielder.

Almost another one! Verreynne takes his bottom hand off the bat and tries to fend it away, but it falls just short of gully.

Verreynne gets deep in his crease and smacks a cross-bat shot through point.

He's wisely playing back on this slow deck, but if one spins and stays low, it'll be tough to keep out.

Marco Jansen comes to the crease and wears a bouncer in the bicep to start.

Oh they go up for another one! Almost identical to Zondo's, but it's given not out, and ball tracking shows it was juuuuuuust pitching outside leg. Cummins was fighting every fibre of his being to review that and chose ... wisely.

Asolutely plumb LBW with the double bluff from around the wicket.

Khaya Zondo reviews, but that's one of the worst I've ever seen. A right-armer around the wicket to a right-hander will often pitch outside leg, but that was a genuine yorker, so it was completely smashing low on middle stump.

He was expecting another short ball and the surprise yorker (not a massive weapon for him usually) gets Zondo, who's not happy. I think he thinks he got an edge.

Good bouncer is fended down by Zondo. Still no short leg.

Oh. Here he comes. Travis Head gets in there.

And he comes around the wicket to the right-handed Zondo. Short ball telegraphed a bit, so it's calmly ducked.

Verreynne leaves one alone outside off and it rips back towards off stump. Not enough, but it'll put some doubt in the batters' minds.

Four! Slapped behind point with the reverse sweep.

And then driven through cover for two more. Verreynne looking solid so far.

Zondo's almost strangled down the leg side. Would've been the third for the innings.

And then he pushes at a shorter ball outside off. Edges and gloves very in play.

Cummins finally gets full and Zondo simply leans on it to get a couple past gully.

Horrid attempt at a pull shot from Zondo, who follows a loopy bouncer. He was very lucky not to get anything on that.

Excellent over from Cummins. This pitch map won't be as consistent as the rest of his, but it's what the game situation calls for.

Four! Full, wide and crushed through cover with a slap from Khaya Zondo. He spoke during drinks about wanting to bowl full into rough and get the batters on the front foot, but not like that.

Bang. Short and slapped through square leg by Zondo. But there's a boundary rider on that side.

The artificial light is having a bit of an effect, shining off Lyon's dome.

SKIED... but Renshaw can't get to it! Zondo whacked another one over square leg and Renshaw dives forward but it bounces just in front of him.

Dropped! Verreynne smashes a short one through mid-wicket, where Agar gets an outstretched hand to it, but it juuuuust comes out. Would have been an absolute all-timer, and he almost pulled it off.