Hashim Amla and Jacques Kallis put on an unbeaten stand of 143 to help South Africa to an 18-run lead over England on day three of the first Test at The Oval on Saturday.
At stumps, Amla was unbeaten on 183 and giving him company was Kallis on 82.
Amla's innings was inclusive of 22 hits to the fence while Kallis had hit 10 boundaries.
Earlier, Graeme Smith scored a century in his 100th Test before he was dismissed for 131. Smith's landmark innings, his 25th test hundred and only the seventh time a player had scored a century in his 100th Test, ended when he played on to Tim Bresnan.
The South Africa captain got an inside edge to Bresnan that deflected on to his back leg and then against the stumps. It was an unlucky way to go but he had still done enough to mark his own special occasion while placing his team in a strong position after an inauspicious first day.
With a flat pitch and sunshine making perfect batting conditions Smith and Amla cashed in to leave England rueing the dropped chance that skipper Andrew Strauss made at first slip the previous evening when Amla was on 40.
Amla's innings has otherwise been faultless and the ease with which his runs came said much about his ability to penetrate the field against quality bowling as much as the conditions.
This was his 15th test century and has so far spanned 261 balls. But for the occasion, Smith's six-hour innings will be remembered more, as he shared in a potentially match-defining partnership of 259 with the right-handed Amla.
The other batsmen to have scored a century in their 100th Tests are Colin Cowdrey, Gordon Greenidge, Javed Miandad, Alec Stewart, Inzamam-ul Haq and Ricky Ponting.
Smith went to 99 with a dab to the third man boundary off Bresnan in the over before lunch, then reached a special century with a back cut for four in the same over.
Smith's innings was a tale of two 50s. His first was the slowest of his career, reaching the milestone in 160 painstaking deliveries as he was especially tested by off spinner Graeme Swann on a turning pitch.
He faced just 41 deliveries to go from 50-100, however, eventually turning the pressure back on to Swann, who conceded 21 runs off the final two overs of his first spell.
England are seeking to hold on to their top ranking while the Proteas can leapfrog England if they win the three-match series. The evidence of the first seven sessions suggests it will be a hard-fought contest to the end.
Photo: Hashim Amla of South Africa celebrates reaching his century during day 3 of the 1st Investec Test Match at The Kia Oval on Saturday (Tom Shaw/Getty Images)