Sources said the trigger for the reform campaign in Asia's third-largest economy came with the return of P Chidambaram as finance minister on August 1.
An eloquent Harvard-educated technocrat with a track record as a reformer, he replaced Pranab Mukherjee, a left-of-centre Congress stalwart who had consistently warned Gandhi against radical reforms that could cost the party votes.
"Pranab was from the old school of Indian politics," said a senior government official, who spoke on condition of anonymity. "The prime minister and the finance minister had to persuade Mrs Gandhi that good economics was good politics."
Her acquiescence in the end led to this month's "big bang Friday" when, a day after taking an axe to costly subsidies on diesel, the government announced that the retail market would be opened to foreign supermarket chains and the bar on foreign investment in both airlines and broadcasters would be lifted.
In sum, these were the most sweeping reforms since Singh took office in 2004 and - in the space of 48 hours - they dispelled the image of a prime minister who was losing his mojo as India's high-trajectory growth faltered.