The answer to Williams hopes in 2021, according to George Russell, could be blowing in the wind.

Over the course of the three days of testing, Russell, Nicholas Latifi and Roy Nissany completed 373 laps, more than Red Bull, McLaren, Aston Martin and Mercedes, while the Briton's best time was good enough for sixth overall, 0.092s off Lewis Hamilton's best on the same compound.

Though reliability doesn't appear to be an issue, and the Mercedes-powered FW43B clearly has pace, Russell fears the car's extreme sensitivity to wind could lead to a "yo-yo" season.

"This test has been a very productive one for the team, we've done an incredible amount of laps, no issues reliability wise," said the youngster, who grabbed the headlines with his performance over the Sakhir Grand Prix weekend last year when he stood-in for Hamilton.

"We knew ahead of the season - and confirmed in these days - that our car was incredibly sensitive to the wind," he admitted. "The conditions of these past three days have brought out the worst of the car, which has been positive in ways to analyse.

"But equally I think you'll see our performance as a bit of a yo-yo this season," he added, "and unfortunately quite often in the hands of the wind.

"We opted to go down a bit of a route to give more downforce," he revealed, "but at the expense of being a bit more sensitive. That was our decision and ultimately, we recognised that if we were consistently at a set pace, as we probably were last year, we consistently won't be scoring points.

"You've only got to be quick at two races for example and you will potentially finish eighth or ninth in the championship," he added, Haas scored three points, Alfa scored eight, we want to try and be as quick as possible when the stars almost align.

"It is uncommon to have three days of testing as we've just seen with the wind strength so it's not as though it's something crazy, every team is experiencing it.

"But it is a small decision we made as ultimately we believe it will produce better results at some races."