Head says Williams capable of podiums

Rosberg set the third fastest lap of the race on his way to fifth position, while Nakajima ran in a strong fourth position early on before he pitted.

"We are beginning to get there," said Head. "Nico has been in the top ten starters every race this year and I think this is Kazuki's second or third time in there, so yes it is progressing.

"But then every team is developing race-by-race and it is up to us to try and develop faster than them.

"Nico happened to find a bit of clear air when whoever was in front of him at the time pitted and he had one lap clear and he set the third fastest lap of the race, 0.3s behind [Sebastian] Vettel.

"I'm not suggesting that that is the true gap (to the Red Bulls) but we just spent too much of the race behind other cars. The car is capable of a podium, but it is like anything - you can talk about it but you need to do it."

Head added that moving up the pecking order in F1 is becoming increasingly difficult with the field so competitive and the pace of development.

"The thing is now a tenth can be a couple of rows on the grid because everybody is so bloody close," he said. "Where as previously you could have said it was nothing it was only a tenth, now that is really valuable.

"Maybe it was a bit more than that, but that is the process that at every race one has got to be bringing developments, otherwise you find yourself sliding backwards."