Pastor Maldonado says he and Williams are in the best shape they have been since they starting working together in Formula 1.
Maldonado was fervent in his praise of Williams's new FW35 after its initial day of running at Barcelona last week, and he was subsequently impressed with its reliability as well.
Asked by AUTOSPORT how progress so far compared with the starts to his previous two seasons with Williams, Maldonado replied: "It's a different story, completely different.
"I'm very happy with the reliability of the car especially.
"We've done a lot of mileage and we didn't have any problems even though this car is completely new.
"It's not the same car as last year with just a changed front wing like many teams have done. This car is a new generation, and it's looking good. All the data we got is very positive."
The 2012 Spanish Grand Prix winner added that Williams had so far only scratched the surface of the car's potential.
"We had some experimental things on the car. We spent our time trying to get some data and we sacrificed on some grounds to get to know the car," said Maldonado.
He also believes the FW35 is turning out to be relatively easy on tyres.
"We planned some more pitstops for the race sim, but we did less," Maldonado said. "We need to check the condition of the others' [race simulations]."
Maldonado did acknowledge, however, that it was still difficult to assess where Williams stood in the pecking order.
"These days everybody says 'the car is better, the season is looking promising,'" he said.
"We can only refer to our car from last year. It's looking better. How much better? We don't know."