Jenson Button's bid to become Formula One world champion has been given a big boost after a court decided that his Brawn GP car doesn't break F1 rules.
Button's team is one of three - the others are Toyota and Williams - that were being judged in the court case.
Button has won the first two races of the season, although only scored half points for the most recent Grand Prix.
Some other F1 teams had complained that the design of those cars wasn't fair, but the judges said they were OK.
Brawn and Toyota have been the two most impressive teams in Formula One this season.
What is a rear diffuser?
It is the back part of the bottom of the car between the rear wheels and under the rear wing
It is crucial to the aerodynamics, and small changes can have a big impact on downforce - and therefore increase grip. This allows the cars to drive faster
They are first and second in the constructors championship and their drivers hold the top four places in the drivers championship.
The arguments were all about a piece of equipment called a rear diffuser which Brawn, Toyota and Williams all use on their cars.
All cars have diffusers but the ones these teams use are larger, and it's thought make their cars around 0.5 seconds a lap quicker.
Race to catch up
Now all the other teams are expected to develop and introduce bigger rear diffusers to put onto their own cars.
One of them, Renault, may have theirs ready for the Chinese Grand Prix, on Sunday 19 April.