In front of a heaving crowd of 86,000, opener Shikhar Dhawan struck a sparkling 137 and Ajinkya Rahane an explosive 79 to fire India to a mammoth 307-7 and ensure their opponents would need a record chase at the stadium to win.
India were then outstanding in the field, sharing the wickets and running out two batsmen as South Africa were skittled for 177 with 10 overs to spare, losing their last seven wickets for 44 runs.
It was India's first win against South Africa at the World Cup after three previous losses.
Though the match may have little consequences for their respective campaigns, India, roared on by a blue-clad, flag-waving army of fans will have reaped a huge confidence boost from downing the highly-fancied South Africans following their emotional opening win over Pakistan.