Williams technical director Pat Symonds believes the Grove team "out to finish third" in the standings this year.
Many believed the legendary F1 squad had the second-fastest car on the grid behind Mercedes during the first few months of the campaign, but they have dropped to fourth in the standings.
Symonds admits the likes of Mercedes and Red Bull are the pace setters and then you have Williams battling it out with several other teams to be next best.
"It is very close this year - no one will say anything other than Mercedes is the best car, in my opinion Red Bull are second, and then you have Ferrari, Force India, Williams and McLaren. That is quite a tight bunch, (but) arguably we have the third-best car at the moment," he told the official Formula 1 website.
After three consecutive podiums through at Austria, Silverstone and Hockenheim through Valtteri Bottas, Williams picked up only 14 points in Hungary before the summer break.
Even though Williams are not able to develop their car at the same rate as some of their rivals, Symonds believes a team effort will help them.
"I don't believe up until Austria that we performed or achieved what we should have, for all sorts of reasons," he said. "What makes it difficult this year is that 43 points are taken by Mercedes at pretty much every weekend, which means the rest of us are fighting for a lot less.
"The difference between finishing third and sixth overall might be quite small. If we are the third-best team, we ought to finish third in the Championship - but in 2005 [when Symonds was executive director of engineering at Renault] we won the Championship with Fernando Alonso despite McLaren having the better car. We were a better team and we won by our racing."