Although Mercedes have a massive lead in the Championships, Rob Smedley is adamant this season has not been decided.
With five wins from five races, including four 1-2 results, Mercedes are running away with this year's Championships.
Lewis Hamilton is leading the Drivers' standings on 100 points, more than double what third-placed Fernando Alonso has scored while Mercedes are 113 ahead of Red Bull in the Constructors' race.
But despite all that, Williams' new head of vehicle performance believes there is still plenty of time for the situation to change especially given Red Bull's "very impressive" RB10.
"I think it would be fairly pessimistic to say that this year has gone," Smedley told Crash.net when asked if the title fights were 'effectively over'.
"If I just talk about the second quickest car - the Red Bull - I'll be quite public in stating that's a very, very impressive machine. If you look at the onboard cameras of that car it's hugely impressive, so with upgrades from the Renault engine things could turn around very quickly.
"The technology - certainly within the power unit - is still fairly immature and the gains we make per race on that side of things are certainly bigger than anything I've been used to for the past years.
"The aerodynamic structure of the car didn't change dramatically but it did change enough that we're still making big gains and looking at new concepts in all the various different areas of the car.
"It's only a matter of time until one of those turns up to have a decent gain and pushes us or other people forward. So no, it's certainly not the end of the season or the end of the road by a long way."
As for Mercedes' challenger, the W05, Smedley says while it is a "decent car" it is their overall package that has given them the advantage.
"They have an excellent power unit package which we are very, very happy to have in the back of the Williams. The Mercedes is a very impressive package, and I think they've produced a decent car. I'm not sure with the same power in the back of all the cars which would be the best.
"Do they have a weakness? Well, clearly not, we've done five races and they've won five of them by a fairly hefty margin..."