Only a "perfect" competitor can knock Lewis Hamilton and Mercedes from their perch at the top of F1.
That is the view of Nico Rosberg, the German who quit motor racing after beating Hamilton to the title in 2016.
He says he has no regrets about stopping, and not just because he does not envy Sebastian Vettel and Ferrari's task of beating the Mercedes "war machine".
"I'm talking about the whole package," Rosberg told La Gazzetta dello Sport. "The car and Lewis.
"To beat them you have to be perfect, and Ferrari has not been able to. I don't find that strange, as the Mercedes team has been more or less the same for five years while there were so many changes at Ferrari."
Rosberg agrees that Vettel's problem in 2018 was his mistakes.
"There were four or five episodes and it does seem to me that the pressure played a role," he said.
"That's not a surprise either. In his role at Ferrari, that is undoubtedly where the pressure is higher than at any other team," said the German.
Fernando Alonso may be retiring, but Rosberg said the future of F1 is in good hands with the likes of Charles Leclerc and 2019 rookies Lando Norris and George Russell.
But he said it's a "shame" Esteban Ocon looks set to lose out.
"It shows that having a link with Mercedes sometimes helps, but it sometimes doesn't," said Rosberg.