Mercedes F1 team turned Nico Rosberg's engine up before it failed

Title contender Rosberg had lost ground from fourth on the grid at the start when he had to dodge around Kimi Raikkonen's near-stationary Ferrari on the line, dropping to sixth.

He regained ground through the race and was closing on Vettel for second place when the car expired in a cloud of smoke three laps from the end.

Mercedes motorsport chief Toto Wolff admitted Rosberg had been given clearance to push the engine harder to chase Vettel.

"We gave it a little push at the end to try to catch Sebastian and this is when it decided to call it a day," he said.

The engine was an old unit put back into Rosberg's car after his new-specification Mercedes V6 developed a problem in final practice on Saturday.

"The engine was on its sixth race, so it was very high on miles," Wolff added.

"And we didn't get any warnings."

TITLE HOPES DAMAGED

Rosberg's retirement and Lewis Hamilton's victory - which he kept after Mercedes was cleared of tyre pressure infringements on both cars - leaves the reigning champion 53 points clear in the standings.

"It's a fact that it's a massive step in the wrong direction," said Rosberg.

"It's the biggest loss I've had in one day throughout the whole season, so that's very bad, and I now need to catch up a few points.

"I keep going. Giving up doesn't exist for me, so I'll just keep fighting, and I've got to try to win the next couple of races somehow."

The root of his problems was a cooling system leak that caused the failure of the new engine, with the older version's lack of power contributing to him qualifying further down the order than usual and creating the possibility for him to be delayed by Raikkonen's issue.

"The whole weekend just went completely wrong, and unlucky I think," Rosberg added.

"So many repercussions of this engine issue... it wasn't an engine issue actually, it was a chassis issue that made me have to change.

"To have it explode two laps from the end was unbelievable. It's even more disappointing.

"I was going to have a good go at Vettel because finally I had the brakes cool enough to attack, and I could ramp up the electric power, and I was going to really go for it."