Toto Wolff has confirmed reports that Ferrari appears to be leading the entire 2019 field by half a second.
"I agree with Franz (Tost)," said the Mercedes boss.
"Realistically, it looks like Ferrari is half a second ahead."
Not only that, the perception in the paddock is that not only Ferrari is ahead of the reigning champions, but Red Bull as well.
"You can't be the favourites for ever," Wolff said in Barcelona. "But we haven't shown everything possible that we can do yet."
However, he admitted that Ferrari is yet to max out its 2019 performance either.
Some believe the reason for Ferrari's lead is its front wing design, with the rules having changed over the winter.
"We appreciate the concept of their car, but we are confident that our choice will work across the season," said Wolff.
"If not, we will have to change the approach, but it will take weeks."
World champion Lewis Hamilton admitted that Ferrari looks "very, very strong" at the first test of 2019.
Sebastian Vettel recently said his car is "close to perfection", to which Hamilton responded to a reporter when told about it: "Good for him."
Even Ferrari team boss Mattia Binotto thinks Mercedes is currently lagging behind.
"Mercedes is good at solving problems. If they are behind, they will catch up quickly," he said.
F1 legend Alain Prost is in Barcelona as a Renault advisor, and he told Auto Bild: "The Ferrari is like on rails, while the Mercedes is more nervous."
