Aerodynamics a key flaw of 2016 Williams F1 car, says Claire Williams

After finishing third in the constructors' championship in 2014 and '15, Williams was pushed back to fifth behind Force India in '16.

Former technical chief Pat Symonds - whose departure from the team was confirmed on Tuesday - conceded mid-season that development had not been strong enough while Valtteri Bottas said Williams had lost performance in high-speed corners while improving in low-speed ones.

"You have to look at areas of weakness and Frank [Williams] has always said performance is aero, aero, aero," Williams told Autosport.

"There are some fundamental flaws when it comes to the performance of the car from that aspect but that is not to point fingers at one department.

"There are areas to improve on across the whole team.

"If we were doing things perfectly, we'd be winning the world championship and we're not."

Williams conceded to being "taken aback" by the challenge posed by Force India but said her team's struggles have "reinvigorated" the outfit ahead of 2017.

"Some of our trackside operations haven't been where they needed to be and our car doesn't have the performance and pace we need it to have," she said.

"We have this situation at Williams where our car suits certain circuits more than others and we need to move away from that, we need to try and get a car that is balanced across all characteristics.

"We've had a bit of a dip this year but it reinvigorates you, not that we were resting on our laurels, it makes you look even harder and more closely at areas you need to improve on and that's what we're doing."

Williams admitted fifth place was "not great financially" but the team will get a funding boost from its deal with Lance Stroll for 2017 and she is confident it has a stable platform for the future.