Indian GP: Rosberg fears Red Bull will be unbeatable

Sebastian Vettel and Mark Webber topped the timesheets during Friday practice in India, with Rosberg sixth fastest and team-mate Lewis Hamilton fourth.

But the German, who struggled with understeer particularly in the second half of afternoon practice, is still confident Mercedes can emerge as best of the rest.

"We are fighting for third place on the podium because the Red Bulls, are just too quick," said Rosberg. "It's doable.

"It's a lot of work ahead of us tonight, but I'm quite confident.

"Pole is out of the question because the Red Bulls are too fast, especially Vettel.

"It's a bit of a pity but that's the way it is, so third place is the target."

But Mark Webber warned that Red Bull's weekend has not all gone smoothly, with work still needed to be done on tyres ahead of tomorrow.

The Australian ended the session just under three-tenths off his team-mate, over one-tenth faster than third-quickest Romain Grosjean.

"Pretty good," he said when asked about the pace of the car.

"We are going OK on both short and longish runs, so we have to go through everything tonight.

"We can talk as much as we want, but it's the race that counts. We have some work to do tonight to improve.

"The car is pretty good, but we need to work on the tyres. We need to make sure they are as consistent as possible and that is the main task on Friday."