Formula One's international court of appeal has reserved its decision on the legality of the Brawn GP car that took Jenson Button to victory in the first two races of the season.
A verdict is not due until tomorrow , when the teams will already be in Shanghai preparing for Sunday's third round of the season.
Ferrari, Red Bull, Renault and BMW-Sauber have appealed against stewards' decisions in Australia and Malaysia that rear diffusers used by Brawn, Toyota and Williams are legal.
The devicechannels the air under and out of the rear of the car to create maximum downforce.
Rivals claim the 'split-level' ones used by Brawn, Toyota and Toyota-powered Williams break the spirit of the rules.
If their appeal is upheld, the championship could be thrown into turmoil with the court having the power to overturn the results and strip Button of his wins.
If not, the Mercedes-powered Brawns can be expected to keep on winning while other teams race to catch up with radical redesigns.