Graeme Smith marked his 100th Test with his 25th hundred, as he and fellow centurion Hashim Amla shut England out in a record partnership at the Kia Oval.
Smith (131) and Amla (131no) batted through almost three successive sessions to set a new highest second-wicket stand for South Africa against England, and sustain the tourists' recovery to the point there was no doubt which team was in charge by tea on day three of this first Investec Test.
In reply to 385 and after opener Alviro Petersen had also made nought on Friday, Smith and Amla put on 259 together out of 277 for two.
Smith batted at a conspicuously uneven tempo, on the way to and beyond his seventh hundred against England and fifth in this country.
The slowest first 50 runs of his 10-year career came from 160 balls, but he then stepped on the accelerator to reach three figures from only 41 more deliveries when he cut Tim Bresnan for his 16th four just before lunch.
By the time he was done, Bresnan bowling him via inside edge and pad with the second new ball in late afternoon, he had been at the crease for more than six hours, kept out 272 balls and hit 20 fours.
England tried to strangle his scoring rate by bowling outside off stump to the left-hander, so adept off his legs but Smith passed the patience test, and it was not until he was past his half-century that he began to milk runs this morning off Graeme Swann.
On a slow pitch, expected to eventually favour spin if the sun stays out, England then hatched a plan to bowl to Smith's strength a little more and post two midwicket catchers to Stuart Broad. But he took the calculated risk, and clipped two more boundaries to take his sudden surge of fours to six from 14 balls. Amla was often more pleasing on the eye.
He reached his 15th hundred from 199 balls, having hit 13 fours, the pick of which were his seventh and eighth - memorable back-foot force past extra-cover off James Anderson and then a drive on the up in the same direction off Broad.
England surprisingly turned to Ravi Bopara, before Bresnan, and then switched Swann to the pavilion end - and there was even an over for Kevin Pietersen before the new ball was taken but nothing Strauss did even hinted at a breakthrough, until Bresnan at last did the trick.