Pakistan's medium pacer Hasan Ali took two wickets off successive deliveries as South Africa reached 26-2 at tea on the second day of the second Test in Rawalpindi on Friday.
Hasan had opener Dean Elgar caught behind for 15 with the fifth delivery of his third over and next ball bowled Rassie van der Dussen for a duck as players walked off for the break.
At tea Aiden Markram was unbeaten on ten as South Africa still trail Pakistan's first innings total of 272 by 246 runs.
Earlier, South African paceman Anrich Nortje grabbed his third five wicket haul with 5-56 to restrict Pakistan's total.