Mercedes says recent problems just "freak" failures

Nico Rosberg's throttle failure at the Russian Grand Prix which put him out of the race was the team's third retirement caused by mechanical issues in four races.

At Monza, Rosberg dropped out close to the end with an engine blow-up, while in Singapore, Lewis Hamilton had to retire after a hose clamp came loose and caused turbo boost problems.

But despite promising investigations in to why there has been a downturn in its finishing record, team bosses Toto Wolff and Paddy Lowe are adamant that the situation is more down to bad luck than anything else.

"I think it is statistical artifact. It is random," said Lowe. "I don't know the exact history of the design of the throttle damper for instance, but it is not something we have changed all year – or even several years."

Wolff added: "I wouldn't be too concerned because the mechanical reliability recently hasn't been good. The failure we had [in Russia] is just a freak failure.

"But definitely if you push the limits of the performance of the car, you are going to find out where the limits are."

Strange, says Rosberg

With Rosberg's throttle problem all but killing off his world championship hopes, he admits the run of reliability problems does not seem normal.

"It is a strange one," he said. "This year we were looking so good on reliability. To then have still a few issues, it is surprising.

"And it has got worse and worse through the season. Especially in the last couple of months, we had loads more issues and race stoppers and things like that.

"We must look into that again and continue to improve that area. It seems we haven't made as big steps as we thought."