On the eve of the 2009 Formula 1 World Championship campaign in the shape of the curtain-raising Australian Grand Prix in Melbourne this weekend, Nico Rosberg and Sir Frank Williams have both contended that this is Williams' 'one big chance' to reverse its seemingly inexorable slide down the sport's pecking order.

The 16-time world championship-winning, independently-owned Grove-based concern has now not triumphed in the top flight since the final grand prix of 2004 in Brazil, courtesy of Juan-Pablo Montoya, and indeed there have only been a handful of podiums in the interceding 71 races.

Williams has finished respectively fifth, eighth, fourth and eighth in the constructors' title chase from 2005 to 2008, with no points total greater than 66, and sinking as low as only eleven in 2006 - and this for a team with no fewer than 113 grand prix victories to its name in seasons past. There really is a sense that with what looks set to be a completely shaken-up playing field 2009, it is truly a case of now or never.

"This is the one big chance that Williams are going to get," Rosberg is quoted as having said by the Daily Telegraph. "If we don't get it right now we don't deserve to get it right."

Those are serious words indeed, and they underline the 23-year-old German's conviction that he deserves better. Arriving in F1 as the inaugural GP2 Series Champion back in 2006, despite showing prodigious raw pace and promise on occasion - such as en route to his breakthrough podium appearances in Australia and Singapore last year - his career has stalled.

With Rosberg already having received overtures from McLaren-Mercedes at the end of the 2007 campaign, Williams is well aware that his young charge - who he rates on a similar level to reigning world champion Lewis Hamilton - will not wait around for a competitive car forever.

He is confident, however, that with on-track results no longer necessarily dictated by the size of each team's chequebook - and a proposed optional ?30 million budget cap in the pipeline for 2010 and beyond - his eponymously-named outfit can roll with the changes and come out fighting.

"Certainly in GP2 they were equal," the 66-year-old mused of Rosberg and Hamilton. "It's unfortunate that he has come during lean years, but I think he is capable of race wins.

"The last thing I would ever say is 'You watch our new car, mate' - but these new aero rules are quite different. We have all gone back to square one, so there is just no bragging going on at all. Absolute silence.

"It's so hard to say where we are. At tests you have no idea how much or little fuel the other cars are running. We could be running around with enough for just five laps whereas they are running around with fuel for a full race distance and people would say 'Wow, Williams are back!' But then first race? Disappointment."

Describing engine partner Toyota as 'a dream', technical director Sam Michael as 'a born racer, very organised' and praising CEO Adam Parr for his 'exceptional brain - he is certainly going to be the man who leads the next generation', it is clear that, credit crunch or no, Williams is confident of weathering the storm and surviving the sport's worst economic crisis in decades. He is himself, after all, a born racer through-and-through - and in any case, he has survived worse.

"Our budget is more than adequately covered until the end of 2010," he underlined, alluding to the Royal Bank of Scotland's recent announcement that it is to withdraw its backing after next season, leaving one of F1's few remaining independent teams in search of a new major sponsor.

"If Bernie [Ecclestone] had rung all the teams this morning and said 'I've got a big international bank willing to commit for two years', I would be killed in the rush to get to him.

"We are Williams, and for us that's very different to being Ferrari, McLaren or Brawn GP. In all of our expressions we want to be the best; we want others to say 'f***ing hell, they're good'. That's what everybody in the pit-lane wants - the team owners, the team principals, the drivers - they want to be the best amongst their peers.

"We're a pretty young team - I'm the oldest person in this building. Most of the people at Williams now make things happen, and that's what you need as we come up to our 40th year. There is massive energy and drive."