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Gorgeous shot from Matthew Breetzke.

Overpitched by Pat Cummins and the right-hander drives elegantly through extra cover for four.

Back-to-back maidens since drinks with Nathan Lyon going over the wicket to the left-hander Ryan Rickelton.

The South Africa batter is happy to pad up to anything pitching outside leg. Plenty of time left in this game, he's in no rush and now isn't the time to take risks.

Maiden over to start from Pat Cummins as Matthew Breetzke blocks the last delivery solidly.

The Australia skipper has now bowled 363 balls since he last took a wicket.

I think Simon Harmer would have something to say about that, Trevor.

Scoring quickly on such a slow surface is not going to be easy either, especially as it starts to deteriorate further.

Anyway, Pat Cummins is going to bowl the first over after drinks. Cooper Connolly's spell last just one over.

That's a ripper!

Nathan Lyon has found some rhythm now. He flights one beautifully to entice the drive, lands it in the rough and the ball turns sharply through the gate as Matthew Breetzke goes at it.

Just misses the timbers and the bounce means Alex Carey can't take it. It's a bye when it could so easily have been a wicket.

Time for drinks after an engrossing first hour at Newlands.

A very welcome over for South Africa.

Nine runs from it as Cooper Connolly struggles to find his length.

After the boundary first ball, five singles follow and the lead is up to 70.

That's what Matthew Breetzke has been waiting for!

Nearly an hour into the day, it's been tough going so when Cooper Connolly offers up a long hop outside off, the Proteas right-hander can't believe his luck - thumped through the off side for four.

Not a great start for the Australia's left-arm spinner.

Frustration for Ryan Rickelton as he misses out on a ball drifting down leg.

All it needed was a little tickle and that was four.

Maiden over from Nathan Lyon.

A pair of singles from Josh Hazlewood's latest and while scoring runs still doesn't seem straightforward on this surface, the threat from the seamers feels minimal with the ball nearly 60 overs old.

The spin of Nathan Lyon at the other end is another matter.

Suddenly, things just get a bit lively as Nathan Lyon lands a few balls in the rough outside Matthew Breetzke's off stump and causes some problems.

The first is a touch short but just catches the footmark and rips back sharply to cramp Breetzke as he shaped to cut.

Out of the rough again next ball and there's an appeal for bat-pad as the ball loops up to short leg. Nothing done.

Breetzke then gets a big stride in and is struck on the pad again. Australia don't think he's playing a shot and appeal for lbw. Not given and, despite a good chat, opt against reviewing.

One from the over and that's a sign of things to come.

Maiden over from Josh Hazlewood as he goes at Ryan Rickelton from round the wicket.

Another bouncer is comfortably ducked and it remains slow going for South Africa on a slow surface.

OK, there's the first ball to really grip and turn this morning from Nathan Lyon.

Cue the "oooh, Gary!" shouts from the fielders around the bat despite Ryan Rickelton leaving it well alone.

The next ball is a drag-down, though, and Rickelton thumps it to deep cover for the only run of the over.

Lyon gets the last ball to catch the footmark and turn sharply into Matthew Breetzke but the right-hander, who has been very chatty this morning, keeps it out.

Josh Hazlewood replaces Mitchell Starc but there's still not a huge amount happening for the bowlers.

Three from the over, all for Ryan Rickelton, with two coming as he guides the ball just wide of gully.

Nathan Lyon will continue from the other end.

I'd agree with that, Ant. Anything over 150 could make for an interesting chase but Australia would still go in as big favourites.

Three from Nathan Lyon's latest, with some good, positive running earning Matthew Breetzke a quick single.

Half an hour into day four and it's been a steady start, just 14 runs and no wickets but the situation and the tension has made it extremely watchable.

Change of angle from Mitchell Starc a couple of balls into the over, going round to Matthew Breetzke.

The Aussie quick bangs in another bouncer soon after and Breetkze easily ducks under it then stays on his haunches looking at Starc.

Eventually he gets up and sticks his tongue out at Starc. The bowler isn't overly impressed and there are a few words at the end of the over.

That didn't take long.

Top shot from Ryan Rickelton.

He goes back, deep into his crease to create the length and punches Nathan Lyon through the covers for the first boundary of the morning.

The umpire steps in for a quick word with Mitchell Starc, I'm not sure if that is to do with his follow through - he's close to that danger area - or the way he kicks at the crease.

Either way, if Starc is trying to do anything to help Nathan Lyon, it's worth remembering that South Africa spinner Simon Harmer could also benefit later in the game.