Felipe Massa has taken issue with reports that Williams have been too conservative with the design of their 2016 car.
Following the FW38's launch, a correspondent from Brazil had reported his "disappointment" that the new car is visibly almost identical to its predecessor.
However, Massa insisted to Globo Esporte: "The car is a lot different, although I don't want to talk about the technical details."
Teammate Valtteri Bottas, seventh on Tuesday's Barcelona timesheets, added: "We have addressed the weaknesses of the 2015 car. And you can feel it."
Bottas, however, said he has "no idea" where Williams is relative to the competition at this point, but reiterated that his goal for 2016 is to win races.
