South Africa's openers have taken advantage of a wayward Bangladesh attack to go to lunch at 0-126 on Friday's first day of the second Test in Bloemfontein.
Dean Elgar and Aiden Markram reached half-centuries before the break.
Elgar became the first player to make 1000 Test runs this year and was 72 not out at lunch. Markram, in his second Test, was unbeaten on 54 as South Africa scored at more than four runs an over.
Bangladesh won the toss and elected to bowl on a wicket that was expected to be green and bowler-friendly but proved much flatter than anticipated.
Mixed in with some mediocre deliveries, they handed the home side the chance to build a foundation as they seek to sweep the two-Test series.
The pair also made a strong start to the first Test in Potchefstroom when they put together a 196-run partnership which laid the foundation for South Africa's 333-run victory.
