Button must fend off 'Kate's Dirty Sister'

Sebastian Vettel pictured after his win in China earlier this season (GETTY IMAGES)

Sebastian Vettel and the Red Bull car he calls 'Kate's Dirty Sister' have given Formula One championship leader Jenson Button plenty to think about ahead of Sunday's Bahrain Grand Prix.

The eye-catching moniker came to light after Vettel powered through rain, spray and treacherous standing water to hand his team a breakthrough first victory at the Shanghai circuit last weekend.

"Like a ship, a car should be named after a girl as it's sexy," the 21-year-old German explained to reporters when asked about the name stuck on the dashboard of his car.

"My original car was called Kate. But then it got smashed at the opening race in Australia. So we called this one Kate's Dirty Sister because it is more aggressive and faster."

That was evident in China, with Vettel leading Australian team mate Mark Webber to a one-two finish ahead of Button's third-placed Brawn.

Button had won the first two races in Australia, where Vettel crashed, and Malaysia from pole position with rivals fearing Brawn could have the championship wrapped up early thanks to their controversial rear diffuser.

It does not look that way now. Red Bull are breathing down Brawn's neck while other teams are rushing their own 'double-decker' diffusers into play.

"We still have a lot more to come, we have a lot in the pipeline," team boss Christian Horner told the autosport.com website.

"It is too early to say whether this is a championship challenge but we are firmly on the scoreboard."

Unless Bahrain suffers the same fate as the rain-delayed MotoGP season-opener in Qatar, Sunday's race at the desert Sakhir circuit should be both hot and dry.

That could turn the balance back towards Brawn, whose cars qualified with considerably more fuel on board than those ahead of them in Shanghai but whose strategy was undone by the atrocious conditions.

Renault, who rushed out a new floor and diffuser for Shanghai and have the advantage of the KERS energy recovery system that Brawn and Red Bull are not using, could also come more into the picture while Toyota tested in Bahrain pre-season.

Renault's double world champion Fernando Alonso has won twice there before.

So too has Felipe Massa, whose Ferrari team have yet to score a point in three races and will suffer their worst ever start to a season if they draw another blank.

The Gulf kingdom has been good for both Ferrari and Massa with the Brazilian chasing his third win in a row at Sakhir after leading team mate Kimi Raikkonen in a one-two last year.

Massa, who also arrived at Sakhir without a point to his credit in 2008, hopes to have the KERS system back on his car this weekend after Ferrari ditched it for China.

"Bahrain is a very important track for KERS, so I hope we can be more competitive," he said.

Poland's Robert Kubica handed BMW-Sauber their first Formula One pole in Bahrain last year but, like Massa and Raikkonen, is also empty-handed in a season turned upside down by new regulations.

McLaren's world champion Lewis Hamilton, runner-up in Bahrain in 2007, is another one struggling to come to terms with changed circumstances but he also has KERS on his side.

"We should have a few new components at Bahrain so I hope we'll continue with our progress," said the Briton, who has just four points.

"I still think we are several races away from being truly competitive but a straightforward race in Bahrain would give us a very good opportunity to accurately assess where we sit among our rivals."