The team overhauled its challenger for this season but as Williams chief technical officer Paddy Lowe explains in an exclusive interview for this week's issue of Autosport magazine, "a number of those more radical design changes didn't really work for us".

The FW41's aggressively undercut sidepods is one radical misstep that has helped contribute to the car suffering a diffuser stall problem and corner-entry.

Williams has made staffing changes this season as it bids to recover from those errors and also launched an internal review into its processes to work out where it went wrong.

Rookie driver Sirotkin said: "It's all based on very much fundamental understanding and, let's say, on the process we build the car.

"It's all started from there and that is why it took us so long to understand it properly and to get over it.

"I think we learned many lessons about the procedure from zero to the end, and I think the way we are approaching the new car it's going to be quite a different process.

"So we can avoid the issues we suddenly found this year, and then obviously put more performance on it."

Sirotkin has not been confirmed for a second season with Williams but has been a regular visitor to its Grove headquarters throughout his maiden campaign in F1.

The Russian has spoken regularly of his desire to play a part in Williams rebuilding itself into a leading team and said he had seen encouraging signs for 2019 on recent visits to the factory.

"I don't want to be too optimistic, but it looked already quite a big step better," said Sirotkin. "It's the situation exactly [the same as] this time last year, about the current car.

"It is a step ahead, which is always good. I don't want to say we will be immediately back and we'll be 100% as we want, but for sure it looks like we learned a lesson."

Lowe said it was "absolutely right" that Williams needed to be able to identify differences in its approach to the 2019 car as much as be able to see improvements on the data.

"We're not just going to turn the same handle and say we've made a good step forward," said Lowe. "We've got to approach things in a different and better way.

"None of this stuff is easy, overnight stuff. It's the nature of the competition. There aren't any promises as to what can be absolutely achieved by doing that.

"But I'm confident we will turn that direction around."