South Africa posted 140 for 6 on Monday in an action-packed first day of the opening Test, after Bangladesh collapsed to 106 all out with Kagiso Rabada celebrating being the fastest to take 300 Test wickets.
The visitors took the lead, reaching 140 for 6 in 41 overs in reply at stumps at Mirpur, with Wiaan Mulder and Kyle Verreynne not out for 17 and 18 respectively.
Bangladesh won the toss and opted to bat but four of their top six batsmen failed to reach double figures, with opener Mahmudul Hasan Joy top-scoring with 30 on a lively pitch.
Seamers Rabada, Mulder and left-arm spinner Keshav Maharaj took three wickets apiece for South Africa. He managed the feat in 11,817 balls, the fastest of all time, beating Pakistan's Waqar Younis (12,602 balls).