Four! Ngidi slashes through cover and it makes it all the way to the rope. He may have rather it had stopped just short so they could rotate the strike with three, but no such luck.

Vicious bouncer at Ngidi, who sort of falls backwards out of the way. Ugly, but he's unhurt and his wicket is still intact.

Ngidi has done well facing Starc thus far, but this is a real test now.

He slashes away through the off side, and the South Africans jog through for a single.

The defence of Zondo is steadfast.

Very wide and Zondo has a massive slash at it, but misses everything.

He tries the bouncer, which does no damage, but makes sure Zondo can't steal the strike to start the next over.

Zondo crushes a very short ball with a powerful hook shot. A majestic shot for none.

EDGED ... for four! Didn't move his feet at all, just bunted at the ball with his arms and only just missed chopping on to his stumps.

Four more, this time with intent through mid-wicket. Australia can't get too loose, because if this lead can become 60 in a flash, and that could be very uncomfortable on this pitch.

BOOM! That's a hat-trick of fours for the stand-and-deliver man.

A big swing and a miss. Marnus is up, but almost no-one else is. Still, Cummins burns a review. They have three available so might as well.

Not out.

Cummins sprays it down leg, and that will give Ngidi the strike to start the next over.

Big swing and a miss outside off. Again, no footwork and no ball contact.

Zondo punches into the off side and pushes Ngidi to get through for two. The big man digs deep and gets back on Labuschagne's admittedly wayward throw.

Zondo tries to clear the rope with a cross-bat slog, but it falls on the edge of the ring. No run taken.

Starc will have two balls at Ngidi after Zondo clips a yorker off his toes behind square.

Another full ball from around the wicket and Ngidi has a big swing at it, missing everything. Not going to die wondering.

He makes it through, and that's one more over ticked off. The lead is 16.

The right-hander faces up, and it's slapped around the corner. Bit of a nothing delivery on Zondo's hip really. Neither here nor there.

Four! Uppercut by Zondo. Might as well throw the bat around.

The field comes up on the penultimate ball of the over, but Zondo clips through the in-field to give Ngidi one ball against Cummins.

And the number 11 keeps it out.

Khaya Zondo defends and ... runs? Not protecting number 11 Lungi Ngidi? Interesting choice.

Starc is around the wicket to Ngidi, and rips it past the outside edge.

Ngidi gets in behind one to defend. How long can he last?

Runs! Four through the gully! Ngidi drives and gets a thick edge between gully and backward point.

Another one past the outside edge. The way Ngidi is jumping around, you'd have to think a well placed yorker is going to collect some stumps.

Starc goes full, but Ngidi just clips it fine and they don't take the runs.

Another edge, this time from Anrich Nortje, and another Cameron Green catch in the gully.

Pat Cummins has two in a row, but that's the end of the over and there's only one wicket to left in the innings. Will he even have a chance to nab the third?

Just behind the top-of-off length, going across Rabada, who just pushes at it and gets a healthy edge through Alex Carey.

Cummins has brought himself on to bowl at the tail, rather than have Nathan Lyon bowl to the left-handed Rabada. Who am I to question Pat, but Lyon seems very likely to mop up here.

Big drive from Rabada, but no bat-on-ball contact. Missed it by a mile in the end, really.

That short leg I was asking for is in now and Cummins bangs in a bouncer, which Rabada just manages to avoid.

He's on the money and beaten Rabada's outside edge straight away.

Oh the yorker is dug out very well, and Rabada scurries through for a single.

South Africa hits the lead! Cop that, Australia.

Starc comes around the wicket to Khaya Zondo and the angle is troubling, although he manages to work a single.

Rabada works off the hip for one more, and steals the strike. Interesting that there hasn't been a short leg in for the seamers all day.

Well, the scores are level, but with South Africa's very flimsy tail all that's standing between Australia's bowlers and any sort of target, I can't see this lasting too much longer after this break.

Yesterday, Kyle Verreynne said the quality of their bowling attack meant that whatever the score on the board, it felt like they would be able to defend it.

He probably didn't mean this low though.

Still, there's plenty of time and perhaps the South Africans can frustrate Australia enough to give them something to go for.

Zondo is forward, defending, the first couple of balls.

He turns the next towards David Warner at deep leg gully for a single.

Bat pad and slip for Rabada, fine leg, fly slip and point in place too.

Rabada plays the ball away square for a single.

The scores are level, Australia will have to bat again

And that's tea.

Not a bouncer, just a very nicely directed ball outside off - right down the corridor of uncertainty and Maharaj just played it off the outside edge to Carey behind the stumps.

He goes for 16 off 18 balls.

South Africa are still 2 runs behind...

Rabada is the new man and he lets the ball fly past to end the over.

BEATEN! Maharaj looked to play a drive but it was never there and the ball flies past the outside edge.

BEATEN AGAIN! This time Maharaj played down the line off the back foot and the ball flew past the outside edge.

Four! Driven square for a boundary - nicely played by Maharaj.

EDGED! Four! That's off the inside edge, it's flown past the stumps by a whisker and down to the boundary.

Square leg has been pulled back -bouncer indicator alert...

Forward defence from Maharaj.

Four! Stepping back and cutting to the deep backward square leg boundary. Nice shot.

He tries again but he'll only get a single as Boland has been moved back to the deep backward square leg boundary.

Zondo turns the ball away for no run.

South Africa needs 10 to make Australia bat again.

Well, you weren't going to take him off after that last one, are you?

Incidentally, that last over was the fifth time in Test cricket that Boland has taken multiple poles in an over.

Zondo defends but the ball almost drops onto his stumps.

Zondo is pretty solid here - no runs but he's getting that bat forward and not leaving any gap between it and his front pad.

Slip, leg slip, bat pad, cover, mid off, long on, deep square leg, short third man.

Driven by Maharaj, a lazy swish of the bat through cover for two.

He's back forward defending now. No run.

He does well to fend the ball to short leg and not allow it to pop up.

And he tries again but can't make much contact.

Back defending deep inside his crease now is Maharaj.

Boland drops back to the third man boundary for the last ball, but Maharaj defends solidly to end the over.

Huge sigh around the ground as Maharaj gets forward and defends a ball straight back down the pitch.

Maharaj repeats the dose but angles it to cover and takes a single off the last ball.

South Africa need 17 runs to make Australia bat again.

Don't count on them getting them...