Pakistan take control after Rabada's milestone

Yasir Shah has begun spinning Pakistan towards a first Test victory over South Africa and is planning to weave further webs on the penultimate day in Karachi.

Shah's three wickets left South Africa in trouble at 4-187 in their second innings after day three on Thursday.

Aiden Markram and Rassie van der Dussen had led South Africa's resistance in overturning a 158-run first-innings deficit, their half-centuries in a gritty 127-run stand nosing the Proteas ahead after tea.

Yet both batsmen were dismissed within the day's last 33 balls, along with Faf du Plessis for 10, leaving South Africa effectively tottering at 4-29 with two days to play.

Legspinner Yasir had bagged 3-53 to go with three wickets in the first innings, while and Nauman Ali has 1-27.

"The wicket has started to take turn and there is also some bounce for the spinners," Shah said. 

"We will try to bowl them out quickly so that we do not have to chase that many runs for victory."

Markram made 74 and van der Dussen 64, digging in together for nearly three-and-a-half hours.

At stumps, captain Quinton de Kock was yet to score and nightwatchman Keshav Maharaj was two not out.

In the morning, Pakistan had been bowled out for 378 with Shah leading the tailenders with an unbeaten and invaluable 38 runs.

Kagiso Rabada's 200th Test wicket was the highlight for South Africa after Pakistan resumed on day three at 8-308.

Rabada reached the milestone in his first over of the day when he uprooted Hasan Ali's middle stump as the batsman attempted a reckless pull on 21.

The fast bowler, playing his 44th test, became the youngest South African at 25 to take 200 wickets. His innings figures were 3-70.

Rabada delivered 8,154 balls to become the third fastest bowler to 200 wickets in Test history in terms of balls, after Pakistan bowling coach Waqar Younis (7,730) and Dale Steyn (7,848).

He also has the best strike rate of all bowlers to have taken 200 wickets.

"It's a massive feat to be included in a list of such names," said Rabada, playing his first Test in a year. "It is satisfying. But the show goes on."

South Africa scored only 47 runs in the middle session and lost Dean Elgar, for 29 to Shah when wicketkeeper Mohammad Rizwan dived full length in front of the stumps and plucked a stunning two-handed catch.

Shah ended the threatening stand by having van der Dussen caught close to the wicket, and then had du Plessis plumb leg before wicket off a sharp googly. 

Nauman secured Pakistan's advantage when he induced Markram forward to block and the ball nicked the bat's shoulder to give Abid Ali his second catch at silly point.