Mercedes team boss Ross Brawn has admitted that he did not anticipate the struggles that the team faced in the Bahrain Grand Prix.

Nico Rosberg could only secure ninth position despite entering the race on pole, while British drive Lewis Hamilton finished fifth after struggling in the early stages.

"To be honest, we didn't anticipate quite such difficulty. It was worse than we expected," he told AutoSport.

"We knew before we went there that if we could get on top of things there, it would be a pretty encouraging sign.

"But I think we're not far off because in the second half of the race when it cooled down a little bit, Lewis was able to pick the ball up and run with it again. He had certainly struggled in the first half of the race."

Sebastian Vettel triumphed last weekend.