STATE OF PLAY: South Africa is in sound position on 329 for five, but need to consolidate against the second new ball that is 10 overs old. If Quinton de Kock, on 25, and Temba Bavuma, on 32, can increase their 56-run partnership substantially, 450 is on the cards at SuperSport Park.
BAVUMA-MAGIC: Can Temba Bavuma reproduce the century that made him a celebrity at PPC Newlands? England's premier goal would be to separate Bavuma and Quinton de Kock early and open the door to the batting tail. Bavuma would want to consolidate and build on his splendid cameo of 32.
COOK-WAVES: Stephen Cook's century on test debut, the sixth by a South African in tests, has dominated the news. His father, Jimmy, was out first ball in his first test for South Africa. Jimmy, though, was an awesome player who averaged 50.58 in first-class cricket. Jimmy told his son: "Well done, my boy. I am proud of you. You did better than me. I got a first-baller."
ENGLAND-GOAL: You don't need to be a professor in physics to work out England's first goal. They want to limit South Africa to 360 by striking regularly in the first half an hour as the second new ball is just 10 overs old. Temba Bavuma and Quinton de Kock want to deny them and get the ball rolling as they resume on 329 for five.
OPENER DEBATE SETTLED: HD Ackerman, a former SA player, says Stephen Cook has settled the argument about the opening combination, and that combination will probably be used in the next two series, against New Zealand and Sri Lanka. But consistency of performances will still be key.
BAVUMA-TECHNIQUE: Kepler Wessels, a former SA captain, has sung the praises of Temba Bavuma's technique. His weight transfer is much better than it was in India, according to Wessels. Bavuma will resume on 32 on Saturday.
INTENSITY GONE: England was without intensity on Friday, because they have won the series and the job has been done. That was their greatest shortcoming, said David Lloyd, a former England coach. If South Africa wins at SuperSport Park, they will move to number 2 on the ICC test rankings.
ENGLAND-TACTICS: England knows Quinton de Kock is an impulsive hooker, so they have two players behind square on the leg-side in position. Stuart Broad is sure to target him with the short stuff.
DROPPED: Quinton de Kock plays away from his body to an out-swinger from James Anderson and is dropped in the gully by Ben Stokes, normally a brilliant fielder. Anderson's woes continues. De Kock had 28 at the time and South Africa was on 335 for five.
CATCHING WOES: England has been talked up as a potential world champion side. They have a brilliant team, but their catching has been below-par against South Africa They dropped 11 catches at PPC Newlands in the second test, and at SuperSport Park, they have spilled three catches so far.
FLASH: Quinton de Kock flashes hard twice to strike two consecutive boundaries off Stuart Broad. The first was speculative over the slips, the second was through the covers, a more convincing flay. He is in attacking mood now that the batting tail is with him.
ABBOTT-BATTING: It is a bit mystifying that Kyle Abbott is below Kagiso Rabada in the batting order. He averages 17.45 in first-class cricketer and can hang around. He has scored four first-class 50's.
SHOT: Quinton de Kock hits a straight drive past mid-off off James Anderson to move to 42. That was the shot of the morning, a glorious cricket shot and South Africa is on 349 for seven. England moves Alex Hales to just behind square on the leg-side. Short balls coming.
BROAD-PLAN: Stuart Broad has peppered Kyle Abbott with the short deliveries and his follow-up ball has caught the inside edge. Abbott survives, but it is clear that Broad will target him with chin music.
ARSENAL, LIVERPOOL AND CHELSEA: There are a number of soccer flags on supporters shirts at SuperSport Park, one of Arsenal, one of Liverpool and even a Chelsea-flag.
CLOSE SHAVE: Kyle Abbott edges a delivery by Ben Stokes in his first over past second slip for a boundary. Now Alistair Cook fortifies the slips with a third slip. He also has a gully. Stokes is bowling well. South Africa is on 364 for seven.
SIX: Kyle Abbott waltzes down the crease and dispatches Moeen Ali over wide long-on for six as the partnership for the eighth wicket grows to 35.
SHOT: Quinton de Kock is dismissive when he pulls a long hop from Moeen Al for a six and hits the next ball past the square point for four. South Africa moves to 382 for seven. South Africa is rollicking along beautifully as the players take a drink.
ASSESSMENT: England took two wickets in the first 15 minutes of play and looked temporarily in control, but Quinton de Kock has powered South Africa to 382 for seven, as 53 runs were scored in the first hour.
GONE: Kyle Abbott is trapped in front for 16 by Ben Stokes as South Africa slips to 386 for eight. It was an excellent fuller delivery that tracked back a bit. But it was a good partnership of 50.
HEAD-SCRATCHING: Quinton de Kock has taken a single off the first delivery again, something he has done repeatedly, while not protecting the batting tail. Maybe he knows Dane Piedt well, and believes that he can bat. Chris Woakes has five deliveries to the new batsman.
SHOT: Quinton de Kock plays an exquisitely timed pull shot off Chris Woakes for four. He has so much time to play his shots. South Africa is on the brink of 400. Dane Piedt is important here with SA on 395 for eight. He must hang around and let De Kock take it to England.
COSTUMES: The costumes at SuperSport Park are adding colour and atmosphere - men in army uniforms and the beards in the white tent - thrilling stuff.