Michael Schumacher on Friday confirmed he is now feeling more comfortable at the wheel of his 2010 Mercedes.
Earlier at the Circuit de Catalunya, his younger brother Ralf remarked that "everything for Michael looks a whole lot better" as he outpaced the sister car driven by Nico Rosberg in both 90-minute sessions.
"Here I'm feeling comfortable with the car, it does do what I'm asking it to do," said the German, after driving the revised W01 car with a longer wheelbase.
Nico Rosberg, meanwhile - who had previously been outpaced by Schumacher in just four other official sessions this season - said he "went wrong on the setup" of the updated car.
It had been suggested prior to the weekend that the changes implemented by Mercedes might suit Schumacher but cause Rosberg, who is currently second in the world championship and 40 points ahead of his teammate, to suffer.
"I'm not sure, we'll have to see," team boss Ross Brawn told the Evening Standard last week when confronted with the theory.