Higher oil prices and lower taxes fuelled Rosneft to a 181 billion roubles ($5.8 billion) net income in the third-quarter, the company said on Thursday.

Analysts polled by Reuters had expected third-quarter net of 137.2 billion roubles at the company, set to become the world's top listed oil producer after its $55 billion acquisition of TNK-BP.

Rosneft's performance is a further feather in the cap of its chief executive, Igor Sechin, a close ally of President Vladimir Putin. This year the company signed landmark agreements with ExxonMobil, Statoil and Eni to tap vast Arctic offshore resources.

Rosneft also said it paid Exxon 2 billion roubles ($63.8 million) for a 30% stake in a project to develop hard-to-recover reserves in the Canadian province of Alberta.

"The Q3 results reflect the beginning of broad-reaching transformations within the company to cut costs and improve efficiency, which have already yielded strong results in production and sales," Sechin said in a statement.

Rosneft's takeover of TNK-BP, expected to close in the next six months, would create the world's largest listed oil company with daily output of 4.6 million barrels in oil-equivalent terms.

Revenue increased 12% to 802 billion roubles from the previous quarter, the company said in a statement, also above analysts' average forecast of 790.9 billion.

Earnings before interest, taxation, depreciation and amortisation (EBITDA) more than doubled to 191 billion roubles, compared with a Reuters poll forecast of 182.3 billion.

Free cashflow increased to 53 billion roubles from 25 billion in April-June.

Rosneft switched to IFRS from U.S. Generally Accepted Accounting Principles (GAAP) late in 2011.