Rob Smedley, Head of Performance Engineering: The weather has been uncharacteristically kind to us so far and is really quite hot. With the Pirelli prescriptions that we're running at the moment the running pressures are very high and therefore the degradation is massive. So I hope we can resolve this with Pirelli. Everyone was degrading the option and the qualifying tyre between three tenths and half a second, which is an amazing amount of degradation. With Valtteri, we lost most of the session this afternoon due to a telemetry issue resulting in an ECU change. Unfortunately, he didn't get a clear run on the supersoft tyre so there's obviously a lot that we can gain there. Felipe was struggling with the balance of the car on both high and low fuel, but we've got some good ideas on what we need to do tonight. What was really encouraging was Valtteri's high fuel pace. I think he had the least degradation out of everybody and his pace was right there with the front running cars.

Valtteri Bottas: We had a small issue in FP2 with the ECU so we had to change it. We lost about half an hour there but otherwise it was a good day. It's great to be back in the car again after the summer break. I really enjoyed it out there today. The car felt decent but I'm sure we can still fine tune the balance and make the car quicker. Our long run pace, compared to the others, wasn't too bad but I think we still need to find everything there is to find. With these temperatures it's very tricky on the tyres and there's a lot of overheating, but it's the same for everyone.

Felipe Massa: It's clear that we've had a very disappointing Friday. It was difficult to get the car working in both the short runs and long runs, and in different set-ups. We've got a lot of work to do tonight to try and understand why the car wasn't working in the way we expected. It's going to be a very long evening but I hope we fix today's issues.

Check out our Friday gallery from Spa, here.