Graeme Smith and Neil McKenzie set a world record opening stand of 415 as South Africa assumed total control in the second Test against Bangladesh.
Resuming on 405 in Chittagong, Smith hit a single in the third over of day two to take the pair to the new mark.
The previous best of 413 was set by India's Pankaj Roy and Vinoo Mankad against New Zealand in Chennai in 1956.
South Africa declared their first innings on 583-7 and in reply the hosts reached 60-3 at stumps on day two.
The tourists began resumed needing just nine runs to break the record and Smith, captaining the Proteas for a record 54th time, bludgeoned a boundary off Shakib Al Hasan in the opening over before retaining the strike with a single.
The left-hander notched two further runs before a single from McKenzie brought the pair level with the 52-year-old mark.
606: DEBATE
Smith wasted little time before stroking a single past square leg four balls later to break the record.
But just one run later the partnership was broken by Abdur Razzak as Smith was bowled for 232 attempting to sweep the slow left-armer.
McKenzie reached his double hundred off 350 balls, hitting 24 fours and three sixes in the process, before being bowled by Shahadat Hossain for 226 - his highest Test knock.
Shahadat also accounted for Hashim Amla and Ashwell Prince before Saqibul Hasan rattled AB de Villiers' stumps and Mohammad Rafique took the wickets of Mark Boucher and Robin Peterson.
On a pitch still conducive to high scoring, Bangladesh made a positive start in response but a triple strike from Dale Steyn left them reeling.
Tamim Iqbal Khan and Junaid Siddique made 39 before the former was caught by de Villiers and the latter edged behind to Boucher.
Captain Mohammad Ashraful then also nicked to Boucher for a golden duck to leave Shahriar Nafees and Razzak at the crease with a massive uphill task.
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