The Italians took a 1-0 half-time lead following a fourth-minute strike from the tournament's leading scorer, Alessia Padalino, who netted from the first penalty corner of the match.
Padalino stretched her personal tally to five goals after three matches in the competition.
South Africa replied five minutes into the second half through Lauren Penny who combined well with Tarryn Bright and Kathleen Taylor.
It was a deserved strike for the unbeaten South Africans after dominating the fixture, particularly in the second period.
Without world record goalscorer Pietie Coetzee, who was ill, they earned 12 penalty corners to Italy's eight, with Kate Woods also hitting the post.
Italian goalkeeper Roberta Lilliu was given the Player of the Match award for keeping her country in the game.
South Africa, ranked 12th in the world, topped the log with seven points from their three games after victories against Poland and the Ukraine.
Their next meeting is against hosts India on Wednesday afternoon before they conclude the round robin stage when they face Canada on Friday.
The top two teams will square off in the final, with the winner given a place at the London Olympic Games in July.
SuperSport, the pay television channel, will broadcast the remaining matches from the tournament.