The secret of Mercedes' speed in Turkey is a Red Bull-style flexible front wing, according to one authoritative publication.
Team boss Ross Brawn said he was surprised with Nico Rosberg's top-three qualifying speed on Saturday "Because we haven't made any dramatic changes to the car" since China.
But the correspondent for Italian newspaper La Stampa, Stefano Mancini, claimed in Turkey that Mercedes has stepped up "thanks to a wing that flexes like Red Bull's."
He also confirmed reports that Ferrari is yet to introduce a similarly flexing wing, that is said to deliver half a second per lap aboard the dominant RB7.
We have improved, that's for sure, but we need another second
Fernando Alonso said he is happy Ferrari took a step forward at Istanbul.
"We have improved, that's for sure, but we need another second," said the Spaniard.
Also disappointed in Turkey is McLaren, with the MP4-26s split by the improving Alonso and both outpaced by Rosberg's Mercedes.
"We just have to keep pushing as hard as we can. I don't like to use the word frustrating, it's just life," said Shanghai winner Lewis Hamilton, fourth on Sunday's grid.