The Proteas' Fakhar Zaman problem persisted in the third ODI series decider when the Pakistani batsman posted 101 runs to help the visitors to 320/7 in their 50 overs.
The score presented a tough total for the Proteas to chase in the gloomy weather conditions in Centurion. Fulcrum batsman and captain Babar Azam also chipped in with a handy 94.
As if wound up by the controversial Wanderers run out during the Pink Day ODI last Sunday, where he scored 193 runs in defeat, Zaman put South Africa to the sword again.
The 30-year-old reached his second successive century in 99 deliveries, hitting nine boundaries and three sixes in the process.
The Proteas keenly felt the missing Indian Premier League (IPL) quintet, especially front-line bowlers Kagiso Rabada, Lungi Ngidi and Anrich Nortje.
The Proteas pace attack lacked bite and threat, barely troubling the Pakistan batsmen under the south Pretoria cloudy skies.
After winning the toss, South Africa unusually opened with Aiden Markram, which showed skipper Temba Bavuma's keenness to innovate.
While the move didn't yield wicket dividends to start, Markram's two overs in the opening spell went for a hugely economical two runs.
The pacemen, Beuran Hendricks, Lutho Sipamla, Andile Phehlukwayo and Daryn Dupavillon, struggled with their lines, with a few wides going down leg side and too many deliveries straying onto the pads if they were not too short.
The mood Pakistan openers Imam-Ul-Haq and Zaman were in meant they did not tolerate anything wayward bowled at them and punished the South African pacemen during their 112-run opening stand.
The overcast morning conditions suggested there could be some assistance for the Proteas bowlers in terms of movement off the air, but they didn't find the correct lengths often enough to get any.
Ul-Haq made it to his 9th ODI half-century from 60 deliveries moments before the pair reached their 100-run partnership from 118 balls that included seven fours and a six.
But Ul-Haq added just seven more runs before departing for 57 (73 balls) to in-form spinner Keshav Maharaj, who had the opener caught at the long-on boundary by Kyle Verreynne.
Zaman reached his 50 after 62 balls, the pair having a brilliant platform from which to propel Pakistan to a mammoth score.
Zaman continued playing with panache and precision, spraying balls to all corners of SuperSport Park, until he raised his bat for the sixth time in ODI cricket.
It took Maharaj, once more, to make the decisive breakthrough when Zaman tried to scoop him behind the wicketkeeper and got it all wrong. Heinrich Klaasen took an easy catch to remove Zaman for a well-crafted 101 from 104 balls.
Maharaj clawed SA back a bit by getting Mohammad Rizwan stumped by Klaasen for 2 before Jon-Jon Smuts accounted for Sarfaraz Ahmed. He finished as the pick of SA's bowlers, with 3/45 from his 10 overs.
Markram eventually got his reward by getting Faheem Ashraf caught and bowled for 1 and Muhammad Nawaz for 4, who was brilliantly caught by Bavuma.
Hasan Ali also added a late 32-run flurry for the visitors.