George Russell says he and teammate Robert Kubica need to work together rather than fight in the wake of Williams' delayed start to winter testing.
Problems with the design of parts meant that Williams, dead last in 2018, was more than two days late to get its new car up and running in Barcelona.
And Russell, the reigning Formula 2 champion, says he and teammate Kubica must now work together.
"We cannot and do not want to be rivals," he is quoted by Eleven Sports.
"We can't fight over 19th place. We want to help Williams to achieve something bigger.
"It will not work if we compete with each other. We need to cooperate," Russell added.
Kubica has given an alarming account of last week's testing for Barcelona, declaring: "After the week I know as much as I did before. Which is nothing."
Russell, though, is looking on the bright side.
"I had a good feeling in the car. It seems balanced," he is quoted by France's Auto Hebdo.
"But we cannot say much yet because I haven't explored the limits of the car. We still need to optimise all the areas because everything was done at the last minute."
