Mixed feelings for Rosberg

Rosberg will lose 10 places on the starting grid after an unscheduled engine change on Saturday.

The German's Cosworth engine, which must last two race distances under Formula One regulations, had suffered damage from being over-revved at the previous U.S. Grand Prix.

Cosworth monitored the engine and decided to change it after Saturday's third and final practice before qualifying for Sunday's race.

The change left Rosberg with a bittersweet taste after qualifying in a strong ninth position.

"I am pleased because it was quite a good qualifying for me today, even if my last flying lap wasn't perfect," said Rosberg. "Even if I had managed a perfect lap, it wouldn't have made a difference anyway because the gap to eighth place is pretty big.

"Dropping 10 places because we had to change the engine isn't ideal, but I've shown in previous races that I can work my way through the field. Our Bridgestone tyres have proved to work well here and that gives us confidence for tomorrow's race."

Teammate Mark Webber, 11th fastest today, will move to the top ten thanks to Rosberg's penalty.

"We knew it was going to be a pretty close qualifying session and the fact that Nico and I are just on the border of the top ten demonstrates that," said Webber. "I had several good laps but my last qualifying lap was not so awesome.

"I wasn't quick enough in the last sector so I lost a couple of tenths. No excuses. Let's see how the race goes tomorrow."