George Russell is worried Ferrari engine gains could scupper Williams' chances of progress in 2021.

Last year, the Briton reached Q2 on nine occasions in qualifying but poor race pace meant his only points came substituting for Lewis Hamilton at Mercedes at the Sakhir Grand Prix.

Expectations for this year are limited with optimism financially under Dorilton ownership and the arrival of Jost Capito as CEO, but development restrictions mean really significant gains are unlikely.

Even so, after a recent filming day in the FW43B, Russell's first impressions are positive.

“I think we’re very hopeful we can continue to go forward,” he told Sky Sports. “The car is definitely a step in the right direction.

“Whether it’s enough, who knows. It all depends on our competitors really so, the team’s done a great a job but until we drive that Saturday evening in Bahrain for qualifying, I don’t think anybody’s going to know."

That's because their main rivals are set for a power boost as Ferrari bring their first engine update in over a year.

"We want to be in the same position as last year [racing Haas and Alfa Romeo] as a bare minimum," Russell told Formula1.com.

"We do appreciate and recognise that the Ferrari power train will take a big step forward so that’s a bit unfortunate for us, so we’ve had to do almost double the work over the winter.

"But that’s the bare minimum [target], fighting and ahead of Alfa Romeo and Haas, which I think is a realistic target and fingers crossed hopefully fighting toward the mid-pack."

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Russell though admits the barometer of his own performance will likely remain the same as it has the past two seasons.

"Following every single race, I know if it’s been a successful weekend or not," he said.

"That doesn’t matter if I have finished 14th in Q2 or only 17th or 18th. I know if I believe I have got the absolute most out of the car or I haven’t, so I think a successful year would be coming away from it and saying, you know what, 75% of the races or more, we got absolutely everything out of it.

"Obviously you can’t achieve it every weekend. I’m just being realistic. [I want to leave each weekend] knowing I didn’t make any stupid mistakes, continuing to improve as a driver, continuing to improve and help the team."