Wayne Parnell is going to have a dart. He's dragged his length back slightly, trying to cramp the Sri Lanka batsman for room. That's an awful bit of fielding from AB - he is human after all - and Rabada, AB first diving onto the ball and Rabada running the wrong way around it. There's still plenty of time left for Sri Lanka.

Here's Tahir's strike, trapping Kapugedera on the crease with a fine delivery.

Four! A proper half-tracker from Tahir and Tharanga doesn't miss a beat, leaning back and pulling it firmly to the boundary. Tharanga then goes to cut and a fine tumbling dive from Chris Morris, throwing himself down to the ground, heads the ball off.

50 for Tharangapublished at 23 overs

23 overs

SL 136-4

Shot! Lovely from Perera, down on one knee and sweeping Duminy to the boundary. That was a pretty ordinary full toss and Duminy pulls his line back slightly to keep the batsmen quiet.

Tharanga brought up his half-century in that last over, which went relatively unnoticed. It came from 59 balls, with five fours.

Graeme Smith
Ex-South Africa captain on BBC Test Match Special

David Miller has been carrying a hamstring injury for a while, I believe, and he doesn't seem to be moving too quickly in the field.

Tahir, headband firmly in place, carries on wheeling in Kusal Perera, who has traded his helmet for a cap. Tharanga drives a little uppishly and the pair dart across for a quick single to bring up the 150. That could have been close to a run out but David Miller, running in from the boundary, was slow to get to it.

Here is that extraordinary run out from De Villiers. Ridiculously good.

Duminy's whizzing through this over, jogging to the crease and whirling his arm over. South Africa's over rate was poor during the series against England and AB will be keen to avoid a ban as captain. Sri Lanka tap a few singles here and there but South Africa keep turning the screw.

It was signaled wide by the umpire but Quinton de Kock had whipped the bails off. I'm not quite sure why it's gone upstairs, mind - Tharanga has both feet firmly in the crease. Not out.

Hello, is this a stumping? We're going upstairs...

Cheers, Steph. I wish I was as good at anything as AB is at cricketing things. Anyway, another change of bowling. Double spin, with JP Duminy into the attack.

Tahir has his long hair tamed by an Alice band. He bounds in, an approach full of enthusiasm and menace. His googly is a WMD. Not picked by Tharanga - South Africa think about reviewing but decide against. Good decision. Here's Amy Lofthouse.

Graeme Smith
Ex-South Africa captain on BBC Test Match Special

Morne Morkel is South Africa's best bowler against left-handers. He's got height and the ability to get the ball to angle in and move away slightly.

Image source, Rex Features

Thanks to Ted on Twitter for pointing out that is the first wicket in this tournament that wasn't caught or run out. Sri Lanka are being squeezed here. You feel like every ball could be a wicket. It seems a long time ago that Niroshan Dickwella was carving it around The Oval. Kusal Perera has arrived to join Tharanga.

Graeme Smith
Ex-South Africa captain on BBC Test Match Special

I'd like to see South Africa attack Tharanga now. He's the experienced player out there and will be feeling the pressure the most.

This one has been turned on its head. Sri Lanka have lost three wickets for 23 runs.

Graeme Smith
Ex-South Africa captain on BBC Test Match Special

Imran Tahir lives on smoothies. He makes them for everyone - it's one of his favourite things to do. That's where he gets his energy from.

Image source, Reuters

Andy Zaltzman
BBC Test Match Special statistician

Is it possible you could give De Villiers man of the match for two pieces of brilliant fielding?