Jenson Button will be favourite to clinch a third win in three races at this weekend's Chinese Grand Prix after the row over the legality of his Brawn GP car's diffuser was settled in the team's favour.
In the first two races of the season, the Briton and his new team have left the rest of Formula One trailing in the air smoothly channelled through the controversial diffusers at the back of their car.
With the governing FIA having declared the structure legal on Wednesday, their rivals now face a scramble to copy the design but it will almost certainly be too little, too late to match the Brawns in Shanghai on Sunday.
Button, who won only half points for his victory in the washout in Malaysia two weeks ago and leads the standings with 15 points to team mate Rubens Barrichello's 10, is now in the unfamiliar position of having to warn against complacency.
"I am understandably delighted with how our season has begun. However, we are only two races in and everyone at the team is aware that our competitors will not stand still," said Button, who was second behind Brazilian Barrichello in the inaugural China race in 2004.
"We fully expect a tough fight from here if we want to continue our early successes."
Toyota, also running with the 'double-decker' diffuser, have been the closest of those competitors so far, claiming third and fourth in Malaysia through Timo Glock and Jarno Trulli.
"Last year I went well there and scored points but I'm hoping to get more than seventh place this weekend, that's for sure," said German Glock.
WORST START
The success of the Brawns and Toyotas have contributed to what look like states of crisis at world champion Lewis Hamilton's McLaren team and that of last year's constructors' champions Ferrari.
McLaren will race under the cloud of the impending FIA hearing into their misleading of the stewards in the season opener in Australia.
Despite having his third place in Melbourne stripped from him over the incident, Hamilton has been doing his best with a poor car but his team mate Heikki Kovalainen has yet to complete a lap.
"Hopefully some of the upgrades we've added for this race will have a benefit," said the 24-year-old Hamilton, who dominated the race weekend in China last year.
"It would be encouraging if we could qualify a little further up the grid and be regularly challenging for points."
Ferrari have rung the changes since a calamitous qualifying session and poor tyre selection in Kuala Lumpur left them with their worst start in 17 years, rock bottom of the championship standings without a point in two races.
"We need to start from zero," said Ferrari driver Felipe Massa, whose team have won three of the five grands prix in China. "We need to get together to understand point by point what is going wrong and try to improve everything."
Team manager Luca Baldisserri has been left back in Italy to work on improvements to the car.
Brazilian Massa and Finn Kimi Raikkonen will be hoping to wring every little bit of advantage out of their new KERS energy recovery system, which should help with overtaking at the end of the long Shanghai straights.
The Chinese round of the championship has moved to its new place on the schedule from the back end of the season, which should mean cooler weather than in previous years but could also increase the prospect of some rain over the weekend.
