The French carmaker says that fuel economy has helped the energy drink-owned team last the distance against cars with more powerful engines.

Mercedes-Benz has a more powerful 2.4 litre V8 engine and is used by many of Red Bull's rivals. According to F1pulse.com, the V8 had carried out 89% of the total possible mileage by F1 cars since its adoption in 2006 with a shelf-life of 2,000km. 

The Renault RS27 engine, used by four teams for the coming season, can clock upto 3,000km and this fuel economy is responsible for giving Red Bull the upper hand. 

"The Mercedes engine is indeed about 15 horse power more powerful than ours," confirmed Renault Sport F1's Jean-Francois Caubet on Sport Bild magazine.

"But in terms of driveability and fuel economy, it is our engine in front. So when it comes to the bottom line, we are a little bit better than Mercedes."

The recent ban on in-race refuelling by the FIA in 2009, due to a need to "to save the costs of transporting refuelling equipment and increase the incentive for engine builders to improve fuel economy", brought a transformation in the engine's fortunes. In the preceding season, Jenson Button, powered by a Mercedes engine, had become the world champion

"Because our consumption is lower, Red Bull can start the races with 15 to 18 litres less petrol in the tank than the competition. That makes a big difference," he said.

Sebastian Vettel's driving and keen interest in the dynamics of his car also played a part in the past two years. The world champion has been credited with a "very fuel efficient" style, and being "extremely interested in the data".

"They are both key factors when the driver wants to use the engine perfectly," added Caubet.

The F1 car manufacturers will have to be prepared for regulations that will change the engine configuration from 2014 onwards with the teams needing to adopt a reduced capacity 1.6 litre V6 turbo engine.