Bernie Ecclestone claims Mercedes had a head-start over its engine rivals at the start of F1's controversial turbo V6 era.
After the 2015 season opener, the F1 supremo on Monday sided with furious Renault-powered Red Bull as the former champions urged F1's governing body to intervene.
Now, Ecclestone says Mercedes got a head-start over 2014 rivals Renault and Ferrari when the new engine rules were being devised.
It is why they had such a strong start last year and they are keeping that advantage now.
"They knew a bit more about the (proposed) power unit," he is quoted by Italy's Sky Sport 24, "because the Mercedes people were in close contact with the FIA in defining the concept of this engine.
"It is why they had such a strong start last year and they are keeping that advantage now," the 84-year-old Briton added.
Ecclestone said efforts to close Mercedes' huge advantage should now be made, even though he admitted that Renault, "who pushed for this revolution, have failed".