Mercedes non-executive chairman Niki Lauda has disagreed with driver Nico Rosberg over the cause of the German’s lack of pace that restricted him to fourth place on the grid for the Italian Grand Prix.
"Nico was not down on power, he had handling problems – too much understeer, he complained about it," said Lauda.
"He couldn't get the car to handle properly for his way of driving and this made a huge difference.
"The surprise for me and everybody was the Ferrari performance. They really came up to a good top speed, and the engine improvement has been shown now, surprisingly enough.
"It's impressive what they've done with their engine from start to here."
But Rosberg blames old-spec engine
But despite Lauda's comments, Rosberg insisted it was his enforced switch back to an older-spec engine that cost him pace today.
"We had to back to an engine that's done six races and every kilometer you lose a bit of power, especially in Monza which is the absolute power track for engine," said Rosberg.
"It's very disappointing that it happened exactly here, that's a really big compromise then and that's the reason why I'm fourth today, which makes the race tough, because I'm also a bit slower than I could be in the race as well.
"It's not ideal and it's going to be difficult to get past the Ferraris."