South Africa completed a series victory over Sri Lanka with a 10-wicket win in the decisive third Test in Cape Town.
Sri Lanka resumed on 138 for four, still 203 runs behind having followed on, but were given hope when Thilan Samaraweera and Angelo Mathews batted through the fourth morning.
Their stand of 142 was ended when Mathews was trapped lbw for 63 by a Vernon Philander delivery which kept low and, although Samaraweera (115 not out) completed a second century in successive Tests, that wicket was the beginning of the end and they were bowled out for 342.
South Africa completed the shortest chase on record when Petersen drove an opening no-ball from Prasad for four, meaning the target was reached without a legitimate delivery being bowled.