Toyota team principal Tadashi Yamashina says he hopes Formula 1 can now put the diffuser despite behind it, following the FIA's ruling that his team's concept is legal.
The FIA's International Court of Appeal on Wednesday rejected complaints from Ferrari, Red Bull Racing and Renault that the double decker diffusers used by Brawn GP, Toyota and Williams were against the regulations.
In a statement issued by Toyota shortly after the announcement, Yamashina said he had every faith that his team was correct from the outset - having consulted the FIA from the start about what it was doing.
"I was confident the Court of Appeal would reach this verdict and I am satisfied with it," he said. "It is important to stress we studied the technical regulations in precise detail, consulting the FIA in our process, and never doubted our car complied with them.
"This has been a challenging period for Formula 1 and I am pleased this issue is now in the past and we can focus on an exciting season on the track."
The Toyota statement added: "As we have maintained throughout, our team studied the wording of the new 2009 regulations in precise detail to ensure we interpreted them correctly.
"We also made full use of the consultation procedure with the FIA which was a helpful process to ensure our interpretation of the technical regulations was correct.
"Therefore we had every confidence that the design of our car would be confirmed as legal, firstly by race stewards in Australia and Malaysia and subsequently by the Court of Appeal."