Hundreds from JP Duminy and Dean Elgar, in a partnership of 250, put the Proteas in dominating position at tea on day three against Australia in Perth.
It was almost the perfect session, but three balls into the final over before tea, Duminy chased a wide one from Peter Siddle to feather a faint edge to the keeper. It brought to an end a magnficent innings of 141 off 225 balls. Elgar went in to tea on an equally impressive 112.
But even with a lead of 293 and seven wickets in hand, the Proteas will not consider themselves safe, probably not until they are offering a total of at least 450 for the Australians to chase.
The two batsmen, though, had done all that was needed and more to ensure the Proteas are in a position to win this game, coming back from 32-4 on the first morning and a first-innings total of 242.
Starting the day on 104-2, the two batsmen consolidated their positions in the first session, putting on 76 off 26 overs. But Duminy, particularly, came out firing after lunch, producing four exquisite cover drives off Mitchell Starc and Josh Hazelwood in the first two overs.
Spinner Nathan Lyon finally brought on, only for Duminy to cut his first ball to the boundary as he raced from 74 at lunch to 96 in 10 deliveries.
His hundred, the fifth of his Test career, took another 17 deliveries to arrive, but it was well worth the wait, coming off 169 balls with 17 fours. It was enhanced by the fact that it came on the ground where he made his debut eight years and 34 Tests ago.
It was chanceless, too. Two heart-stopping thuds on his pads were always too high and not appealed, but there was a let-off immediately after reaching the milestone when a superb yorker from Marsh caught the inside edge and scooted through his legs to the boundary.
The Australians, bereft of inspiration had no hesitation in taking the new ball immediately, but there was little relief as Elgar unleashed two crunching boundaries off Hazelwood’s first over with the shining cherry.
Elgar, who had been on 69 at the first break finally broke through the three figures 21 overs into the second session, having taken 255 balls, with 13 fours and a six. It was a masterclass in solid support and focused concentration.
Both teams will be reminded that in December 2008, South Africa achieved the second-highest successful run-chase in Test history when they reached the victory target of 414 late in the second session on the final day, for the loss of just four wickets.
And they have to factor in that they no longer have Dale Steyn in their attack, sidelined by a broken shoulder.