Rubens Barrichello has hit back at Brawn GP's cynics and detractors, by declaring that not only is the team's car entirely legal - but it is also every bit as fast and a contender for race wins as it has looked during pre-season testing.

With the 2009 Formula 1 World Championship campaign set to rev into life this coming weekend in the Australian Grand Prix in Melbourne, Brawn has thus far gone against all predictions in setting the pace - a pace few of its rivals seem capable of living with.

Having faced extinction following the withdrawal of Honda last December, the Brackley-based operation has risen Phoenix-like from the ashes with a new name, a new conviction and, seemingly, a whole new lease of life - and so has Barrichello.

"It's a very solid car, a brand new machine, with a very reliable and powerful Mercedes engine, so it's not crazy [to think of victory]", the 36-year-old asserted to Spanish newspaper Marca.

"I've been waiting a long time to find a team that can give me the same set-up as Ferrari, but without having to drive for [Michael] Schumacher."

Barrichello claimed all nine of his grand prix victories with the Scuderia, and despite now going into his 17th season in the top flight - having already overtaken Riccardo Patrese's long-standing record for most starts midway through 2008 - he clearly believes he has his best chance of adding to that tally in years.

The experienced Brazilian had fewer words of encouragement, however, for Lewis Hamilton's struggling McLaren-Mercedes outfit, which he reckoned would likely take 'three or four races' to claw back ground - a situation that, in what already looks like being the most open and unpredictable campaign in years with all of the rule changes brought into force, could be too little too late.

In the face of mounting criticism from rival competitors that the new BGP 001 - in company with Williams' FW31 and Toyota's TF109 - is running with an illegal diffuser after cleverly exploiting a loophole in the new aerodynamic regulations in order to generate greater downforce and therefore grip, the S?o Paulista fired back that the car is 'definitely legal'. Other teams are now believed to be hastily re-designing the gearbox housing and rear end of their cars - but those modifications may not arrive until at least the fourth grand prix of the season.

Renault F1 managing director Flavio Briatore has claimed that 'there are two sets of regulations - the one that allows some teams to have the diffuser built in a certain way that is forbidden to others because it's considered illegal; at least three teams don't respect the regulations'.

"You're asking are we legal?" Barrichello said in an interview with the Daily Mirror. "When someone is behind, it is easier to say your rivals are against the rules than to do better work. It's a different way of interpreting the rules, but we've made sure to respect the rules."

"Our team is very much within the regulations," agreed Williams technical director Sam Michael. "I don't know what the fuss is about.

"People are complaining rather than putting their hands up and saying, 'we didn't think of it because we weren't looking at the rules hard enough'."

The FIA has already cleared Williams and Toyota's diffuser designs, and it is understood that the governing body's technical delegate Charlie Whiting attended testing in Spain to similarly inspect the Brawn entry. FIA President Max Mosley has insisted that it is now too late to make a definitive ruling - leading the sport's commercial rights-holder Bernie Ecclestone to suggest that post-race Down Under, 'whoever is not happy is going to stick in a protest'.