Pakistan made gas savings worth over $600 million by playing some of the largest gas firms against each other over the first 10 years of a supply deal.

According to a report from Pakistan State Oil (PSO), the deal came together with Qatar – the world’s largest liquefied gas supplier – back in 2016. It was a rare high-stake deal, the kind that’s carried out behind closed doors, away from public eyes.

Earlier, the supply agreement came to a halt after Qatar refused to lower prices for LNG. In 2015, after Qatar’s refusal, Pakistan had to make it public in the open market to purchase 120 cargoes in two tenders, which soon after brought in bids from BP Plc and Royal Dutch Shell Plc as well as other suppliers.

Negotiations were still underway with QatarGas Operating Co., and the purpose of the tender was to “fetch maximum number of bidders and best price option”. Ultimately, “the strategy helped bring down prices with QatarGas and saved $610 million,” according to the report.

Timeline of How Pakistan Saved Millions Off Gas Supply Deal

Here’s a timeline of how the supply deal got carried out, according to Pakistan State Oil presentation to Senate Standing Committee on Petroleum: