India leads the T20I series 2-1 and will be looking to seal another series win in the fifth and final T20I on Saturday.
India held its nerve despite Jonker's 49 from 24 balls right at the end, which gave South Africa a glimmer of hope after it was down and out at 114-5 in the 17th over chasing 173 to win. Chris Morris took 2/43 and Tabraiz Shamsi managed 1/31.
While defending the tota, medium pacers Rumeli Dhar, Shikha Pandey and left-arm spinner Rajeshwari Gayakwad picked three wickets each as India bowled out South Africa for 112.
Despite the impressive Junior Dala (3/35) having pinned India's stand-in captain Rohit Sharma lbw with the ninth ball of the innings, the visitors still stormed to 57/1 after the completion of the sixth over. IPL has made Indian bowlers thinking bowlers.
The three-match T20I series is now tied at 1-1.
India have played two matches at Newlands during the entire tour and Saturday's fixture will make it three. Then, debutant Christiaan Jonker and old-hand Farhaan Behardien plundered 51 runs in the last three-and-a-half overs but could not get the hosts over the line.
Virat Kohli and his men have dominated South Africa at their own home and this is a remarkable achievement. The two wins came in the 2007 World T20 and as such the hosts have only ever won a singular bilateral T20I game (against England in 2016) at Cape Town.
Yuzvendra Chahal, who was taken to the cleaners (66 runs from four overs) in Johannesburg on Wednesday, is likely to be retained and he might even have an extra spinner for company in Cape Town where spinners can expect a purchase from the wicket. The victor of this match, therefore, will clinch the title in the shortest format.