Home captain Salman Agha won the toss and put the visitors into bat. But the Proteas were reeling early and managed just 110 before their final wicket fell in the 19th over.
The Proteas needed early wickets, but instead they were fetching the ball from the boundary. Saim Ayub was in a dominant mood and opening partner Sahibzada Farhan slammed 54 off 40 before the latter was trapped in front by Corbin Bosch.
But that was all the visitors could celebrate, as Ayub continued his swashbuckling ways to finish with a sparkling 71 not off 38 balls to set up a series decider on Saturday.
Earlier, Pakistan were ruthless with the ball. Seamers Naseem Shah and new man Salman Mirza had the Proteas on the back foot from the first ball. Mirza produced an absolute pearler, getting prodigious inswing to castle Reeza Hendricks in the second half of the innings.
The next over, Quinton de Kock spooned Shah to mid off. Mirza then picked up his second and third in consecutive overs, first deceiving Tony de Zorzi with a slow bouncer then clean bowled Matthew Breetzke.
At 34/4 in the fourth over, the Proteas were wilting. Captain Donavan Ferreira and starboy Dewald Brevis steadied the ship somewhat. All-rounder Farheem Ashraf then got in on the action, luring Brevis into a nothing shot. He would top score for the South Africans with 25 (16).
From there, it was slim pickings the Protreas tali failed to wag. Ashraf went on to bag three more wickets, while he quicks grabbed five wickets between them.