Mark Webber has claimed that as many as ten different drivers could be in contention to win this weekend's season-opening Australian Grand Prix, but the bookmakers have installed an unexpected favourite ahead of the Melbourne event.

With pre-season testing not throwing up any clear frontrunner as teams got to grips with the sweeping rule changes that came into force over the winter, faces both anticipated and unfamiliar took a share of the limelight until Brawn GP entered the fray and started to dominate proceeding sat the final two sessions, at Jerez and Barcelona.

Forcing Webber to include both of its drivers in his prediction, the Brackley-based team may yet show its form to have been the result of low-fuel runs designed to catch the eye, but the local favourite insists that, with McLaren apparently struggling for pace and both Renault and Ferrari not stamping their authority on the timesheets, it is impossible to pick a winner.

"There's ten guys who can win this race - easily," the 32-year old Red Bull Racing driver admitted to journalists, without naming names, "It's very, very open - probably the most open first race we've ever had.

"It is really difficult to read who is doing what, I think it is too close to call. You would expect McLaren maybe to have done a bit more, going by the testing over the last few years. But, apart from that, we all know they are more than capable of turning up in Melbourne and spanking everyone.

"Qualifying's when we really find out outright pace and, Sunday, we'll get a better idea of the longer-run pace. But qualifying's really a good indicator of where the cars are."

While Webber hedges his bets, however, the local bookmakers have wasted little time in naming Brawn's Jensen Button as their favourite for Sunday's grand prix - with team-mate Rubens Barrichello also in the mix - following the team's headline-making testing pace.

"Button is a $4.75 favourite to win at Albert Park when, realistically, we gave him no hope just a few weeks ago," Sportingbet Australia boss Michael Sullivan admitted, "[Brawn's] pre-season pace was unbelievable, and [the team] has shortened from $41 to $7.00 to win the constructors' championship in its first year after taking over from Honda - which would be an amazing effort."

Acknowledging that pre-season testing is often an unreliable indicator of regular season form, Sullivan has included a varied group of drivers among a closely-matched group of favourites. Kimi Raikkonen, Felipe Massa, Fernando Alonso and Barrichello all feature ahead of world champion Lewis Hamilton, with Robert Kubica and Sebastian Vettel also receiving short odds. Webber, meanwhile, is currently a $51 chance to win the race.

"The Ferraris are second and third favourite, and they do look the obvious dangers with 2008 champion Lewis Hamilton a little off the pace in early testing," he noted, "And, while we will all be cheering for Webber, realistically he will need a lot of casualties in front of him to feature on the podium."

Webber's odds may have lengthened as he continues to rehabilitate himself after his leg-breaking accident on November's Pure Tasmania adventure race, but the Australian insists that, while even walking remains difficult, he will have no problems controlling RBR's new machine.

"It will be absolutely sweet, fully healed and not too far away at all," he claimed, "I haven't missed any testing with the RB5 [although], obviously, I missed a bit of testing with last year's car. I haven't missed any mileage with the '09 car, so that was the most important thing for me. We focused on that and we delivered with that. [Albert Park] has always been a pretty good track to me - if I finish - so I hope we can finish with a good run and try and knock a podium out if we can."