|Morkel, far left, celebrates with teammates after taking the wicket of Pakistani batsman Azhar Ali [AFP]
South Africa took charge of the first Test against Pakistan after Morne Morkel and Johan Botha demolished Pakistan for 248 on the third day at the Dubai International Cricket Stadium.
The visitors take a commanding 271-run lead into the fourth day after reaching 139 for two in their second innings on Sunday, after taking a first-innings lead of 132.
At stumps, Hashim Amla on 44 and Jacques Kallis on 32 were at the crease.
Off-spinner Botha dismantled Pakistan's middle order by picking up three quick wickets and Morkel completed a bad day for the designated hosts as he grabbed five for 54.
Pakistan lost their last five wickets for the addition of just 28 runs and face an uphill task to save the Test.
South Africa 1st Innings 380
Pakistan, 1st Innings (overnight 144-2)
M Hafeez c Smith b Harris 60
T Umar lbw Morkel 42
A Ali c Amla b Morkel 56
Y Khan c de Villiers b Botha 35
M-ul-Haq c Amla b Botha 9
U Akmal c Steyn b Botha 4
A Akmal c Boucher b Steyn 10
A Rehman c de Villiers b Morkel 1
U Gul not out 12
W Riaz c Boucher b Morkel 5
S Ajmal c Boucher b Morkel 2
TOTAL: (all out) 248
Fall of wickets: 1-105, 2-111, 3-176, 4-196, 5-202, 6-220, 7-225, 8-228, 9-246, 10-248.
South Africa (2nd innings)
A Petersen lbw Rehman 26
G Smith lbw Ajmal 34
H Amla not out 44
J Kallis not out 32
TOTAL: (for 2 wickets) 139
Fall of wickets: 1-47, 2-76.
Earlier, resuming at 144-2, Azhar Ali (56) and Younis Khan (35) took their third-wicket partnership to 65 runs but Khan departed playing a shot to midwicket where AB de Villiers took a brilliant catch.
Stand-in captain Misbah-ul-Haq failed to keep a ball down and was caught by Hashim Amla at short leg.
Umar Akmal, who only got a chance to play because captain Mohammed Yousuf sustained a groin injury, also did not show the inclination to stay at the wicket. He came down the wicket but managed to get a thick edge that carried to Dale Steyn at point.
At tea, Pakistan were on 214-5. However, the rest of the batting line-up continued to play rash shots and lasted only ten overs into the final session of the day.
Their last eight wickets fell for 72 runs. Ali brought up a laborious 144-ball half-century, his second in a six-Test career, as wickets kept falling at the other end.
He was well-caught by Amla again at short leg as he failed to fend off a short-pitched delivery from Morkel, who was bowling around the wicket and was warned for running on to the pitch.
Morkel ended with figures of 5-54 while Botha finished with 3-61.
South Africa lost Alviro Petersen (26) and Graeme Smith (34) before an unbroken third-wicket stand of 63 between Amla and Kallis guided them to the close of play.