The 24-year-old finished fifth, thanks to the disqualification of Red Bull’s second placed Australian Daniel Ricciardo hours after the race, in a car that showed pre-season`optimism was not misplaced.
Although Germany’s Nico Rosberg took a dominant win for Mercedes at Albert Park, after team mate Lewis Hamilton had retired from pole, Mercedes-powered Williams laid down a marker for the future.
They are still a long way from where they want to be but there is a new sense of optimism, and purpose, about the former champions as they fight back from the wilderness of last year.
“I think Mercedes are a standout team in terms of pace – and I still think there’s another team that’s very quick, they just didn’t really show it today or they made mistakes,” said McLaren’s Jenson Button – who started out with Williams in 2000 – after the race.
Both McLaren drivers ended up on the podium, with Danish rookie Kevin Magnussen second and Button third, to send that team top of the constructors’ standings.
Bottas and new Brazilian team mate Felipe Massa felt it could just as easily have been them.
“If we had a good qualifying, a clean race, we had a car here to fight for the podium,” Bottas said, and Massa – whose car was rear-ended at the start by Caterham’s Japanese Kamui Kobayashi – agreed.
“I would say Australia was a race where we could finish both cars and in a similar position to McLaren, so maybe we were going to be first in the championship,” the former Ferrari driver told reporters.
Both Williams had qualified in the top 10 and ahead of Button, but Bottas dropped to 15th on the grid due to a five place penalty for an unscheduled gearbox change.
He had climbed to sixth when he clouted the wall and had to limp back on three wheels and a rim, with the safety car coming out to enable marshals to clear up debris. The Finn dropped back to 16th – and charged through the field again.
“I’m quite mad about myself for the mistake,” he told Britain’s Sky television. “I just need to learn from it and I’m pretty sure I’m not going to do that kind of mistake again.
“The team have done such a good job here during the winter. It’s going to be a good season,” he added.
Claire Williams, deputy principal of the team founded by her father Frank, said the former champions – winners of nine constructors’ titles between 1980 and 1997 – had come a long way since last year when they scored only five points.
“I think we entered the weekend with lots of high hopes and there was a lot of expectation on us from the media as well but we were really trying to dampen that a bit and not get anyone’s hopes up too high,” she said.
“But coming into the race we really were hoping for both cars to get some strong points.
“It was so disappointing for Felipe to have been knocked out on the first corner but Valtteri drove such an amazing race…I think he overtook more than 20 cars which was phenomenal.”
(Reporting by Alan Baldwin, editing by Justin Palmer)