Williams F1 team in best shape for years - Valtteri Bottas

After finishing only ninth in the 2013 constructors' championship, Williams has had a resurgent winter and is tipped to start the '14 campaign as title favourite Mercedes' closest rival.

"It's been a good feeling," said Bottas. "One thing is clear: we've made good progress from last year, and we are better and stronger as a team.

"Last year at the last test we started to see that the car wasn't performing as well as we were expecting it to, but once we finished Bahrain [this year] we could see it's reliable, it's a good quality car, well built, and it's also quite quick.

"So you can definitely see a boost in motivation in everyone in the team; I feel like the team is now pushing as hard as it has been pushing for years, and that's good to see.

"We have a more competitive car, and what's unknown is how reliable other the teams will be and how much quicker they can go. But we will see very soon."

WARY OF ESTABLISHED TOP TEAMS

Bottas stopped short of predicting where Williams could finish in this weekend's Australian Grand Prix, as he did not think the team's rivals should be underestimated.

"It's very difficult to say what we should expect from the first race, it's difficult to say how much quicker some other teams can go - for example Mercedes, if they can still go quicker, or Ferrari," he said.

"I'm sure McLaren is going to be quick, and it's only a matter of time before Red Bull come back.

"Of course we hope for the best, we hope we're fighting for good points and maybe even podiums, but I think a good target for the first race would be to score good points, the more the better."

His new team-mate Felipe Massa said the atmosphere at Williams was that of a team on the rise.

"I feel the team is really motivated, they want to grow, they want to get better and they want to be back in the good times that Williams had," he said.

"There are new people arriving, some good ideas inside the team, and I'm trying to give as much experience as I can.

"It can be a nice season for us, but how nice I don't know."

Follow the whole Australian GP weekend as it happens with AUTOSPORT Live from 1am UK time on Friday March 14