[Narus63]

Well Christian Horner seems to have decided who's to blame for his cars' fall from domination:

"In the race Seb was really hanging on and doing a really strong job.
"He managed to hold on to Jenson (Button) early on in the race, but then the Ferrraris were just too quick on the straights for us.
"We were just powerless to defend, but Sebastian did nothing wrong. He drove as hard as he could.

TRANSLATION: He was hanging on to a tow as best as he could. That was our only hope of getting a bit of straightline speed, as the Renault engine was palpably not up to the job.
The Ferraris were just too quick on the straights for us, because they aren't lumped with dodgy Renault engines. We are.
"We were just powerless" = Exactly

I wonder how Horner accounts for the fact that Raikonnen and D'Ambrosio had the fastest speeds through the speed trap, and their Renault engines managed to finish the race too!