Felipe Massa has admitted that the Williams cars are not 'up to pace' with the Red Bull duo, after they had a slow start to the British Grand Prix.
The Brazilian driver just about made it into the top 10 in second practice, while teammate Valtteri Bottas finished 12th in the standings.
The Williams team are battling with Ferrari and Red Bull to see who can be the 'best of the rest' behind the Mercedes duo, but Massa admits that his team need to make some quick changes if they are to battle it out come race day.
"The Red Bull was better today and Ferrari were better today so we need to understand that other cars are pushing hard and we need to fix everything," Massa told Sky Sports News.
"I think the most important job we need to do tonight is to concentrate on qualifying on the new tyres because I think for the race we are not far."
Massa and the rest of the field have one more practice session on Saturday morning before qualifying.