
Smriti Mandhana extended her rich vein of form in her maiden tour of South Africa by registering her third fifty-plus score across formats.
Mithali Raj also scored her fourth successive half-century in the 20-over format - her second in the current series against South Africa - to help India secure a nine-wicket victory.
With this win, India took a 2-0 lead in the five-match T20I series.
As many as seven South African batters got into double digits to help the hosts finish with a total of 142 for 7.
Poonam Yadav was the pick of the Indian bowlers, finishing with figures of 2 for 18 from her four overs.
In reply, India rode on a 106-run stand between Mandhana, 57 off 42 and Raj 76 not out off 61, with the latter scoring her third unbeaten half-century in as many innings in T20Is.
India's T20I captain Harmanpreet Kaur struggled to find the boundaries and finished the match without one.
But Raj didn't get the pressure get to India as she found the fence four times in the last four overs, including one off Shabnim Ismail off the first ball of the final over which helped India over the line.