The minimal pressure limits for Spa-Francorchamps were reportedly set at 23.5psi for the front tyres and at 22psi for the rear tyres.

Massa, who was 12th in FP1 and 17th in FP2, said that the high tyre pressures were one of the key issues slowing up his Williams FW38.

"Today the behaviour of the car was pretty difficult. We were struggling a lot - in the short run, in the long run - with the tyres. It was a very difficult Friday. We're going to have a very long evening to try and fix the problem," Massa said.

"I guess also, one of the issues is the tyre pressure, I've never run such a high tyre pressure, like we have [right now], in my whole career. And this is a bit of a joke to be honest.

"I would say everybody is struggling. I'm guessing I'm not the only one who has such a high tyre pressure.

"The car is just completely not on the ground."

Differing accounts

Going by Friday form, Massa offered a rather pessimistic account of Williams' hopes for the weekend, saying the team faced a "long evening" find pace for Saturday.

To the suggestion that Williams expected Spa to suit its package well, he said: "Yeah, which is not the case for Friday. So, we're going to have a very long evening to fix the problem.

"We have some teams that are very competitive like Force India, like McLaren, and this is our target, to be in front of them. They had a good Friday and we didn't. We need to work it out to improve."

Teammate Valtteri Bottas - ninth in FP1 and 16th in FP2 - said that, for his part, it was a "reasonable day", despite him losing half an hour in the latter session for a ECU change.

"If you look at the laptimes, it looks pretty bad. But when I went with the supersoft, everyone went on high fuel and I got stuck in the traffic.

"It didn't feel too bad. I'm sure we can still make the car quicker, make it better balanced.

"I'm still hopeful that tomorrow we're going to be a long stronger and definitely well in the top 10."

Additional reporting by Oleg Karpov

Don’t miss our Belgian GP video preview…