Pakistan paceman Mohammad Asif marked his comeback by taking all four wickets as South Africa reached 254 for four on the second day of the first Test on Friday.
Ashwell Prince (77) and Herschelle Gibbs (58) were the not out batsmen as the home team made a good fist of their reply after Pakistan totalled 313 in their first innings.
Prince and Gibbs shared an unbroken stand of 111 for the fifth wicket.
Asif, playing his first match for his country since he and Shoaib Akhtar tested positive for the banned steroid nandrolone in November, picked up four for 58.
The two pacemen were exonerated last month when a panel ruled they had not had sufficient warning the supplements they were taking could be contaminated by the steroid.
Pakistan lost five wickets for the addition of 71 runs after starting the day on 242 for five. Fast bowler Makhaya Ntini was the chief destroyer with five for 83.
Captain Inzamam-ul-Haq was the first to go, pulling Ntini to Hashim Amla at deep square leg for 42.
A top-edged pull also accounted for Kamran Akmal, who scored 29 before Andre Nel had him caught by Shaun Pollock at wide mid-on.
Ntini completed his five-wicket haul by having Shahid Nazir and Danish Kaneria caught in the slips for 15 and nought respectively.
Nel, who took three for 100, ended the innings when Naved-ul-Hasan (30) skied a return catch to the fast bowler.
Asif then dismissed Graeme Smith and AB de Villiers early to reduce South Africa to eight for two.
Smith edged to wicketkeeper Akmal for a five-ball duck before De Villiers (four) steered a catch to Younis Khan at second slip.
Asif also had Hashim Amla dropped on four by Mohammad Hafeez in the gully.
The Pakistan quickie struck for the third time when Jacques Kallis was caught by Younis at second slip for 18.
Amla and Prince repaired much of the damage with a stand of 90 before Asif had Amla caught behind by Akmal for 71 five overs after tea.
Scorecard
Pakistan (1st innings):
Mohammad Hafeez c Boucher b Ntini 19
Imran Farhat c Amla b Ntini 26
Yasir Hameed c Ntini b Nel 65
Younis Khan c Nel b Pollock 68
Inzamam-ul-Haq c Amla b Ntini 42
Faisal Iqbal c Boucher b Kallis 1
Kamran Akmal c Pollock b Nel 29
Naved-ul-Hasan c and b Nel 30
Shahid Nazir c Gibbs b Ntini 15
Danish Kaneria c Kallis b Ntini 0
Mohammad Asif not out 1
Extras: (b-6 lb-6 nb-3 w-2) 17
Total: (all out, 96.5 overs) 313
Fall of wickets: 1-48, 2-50, 3-183, 4-193, 5-204, 6-256, 7-276, 8-300, 9-313.
Bowling: Ntini 24-3-83-5, Nel 26.5-3-100-3 (w-1), Pollock 18-5-38-1, Kallis 15-3-55-1, Harris 13-2-25-0.
South Africa (1st innings):
A de Villiers c Younis Khan b Mohammad Asif 4
G Smith c Kamran Akmal b Mohammad Asif 0
H Amla c Kamran Akmal b Mohammad Asif 71
J Kallis c Younis Khan b Mohammad Asif 18
A Prince not out 77
H Gibbs not out 58
Extras: (lb-7, nb-19) 26
Total: (for 4 wkts, 75 overs) 254
Fall of wickets: 1-3, 2-8, 3-53, 4-143.
To bat: M Boucher, S Pollock, P Harris, A Nel, M Ntini.
Bowling: Mohammad Asif 16-2-58-4 (nb-11), Naved-ul-Hasan 9-1-48-0 (nb-1), Shahid Nazir 11-1-60-0 (nb-7), Danish Kaneria 27-7-51-0, Mohammad Hafeez 11-1-24-0, Imran Farhat 1-0-6-0.
