Regardless, Ecclestone says Leclerc and Vettel is the strongest driver line-up on the Formula 1 grid.
Leclerc has seven pole positions to his name this year, a tally that cannot be topped with just three races remaining in the season.
However, the Monegasque only has wins in Belgium and Italy to show for his fine debut season with Ferrari, something Ecclestone puts down to his inexperience at the highest level.
“The boy is good, but he’s still making too many mistakes in the Ferrari. Just as Verstappen did at the beginning of his career,” Ecclestone told Blick.
“Only when you relax in the cockpit can you fight for world titles.
“Like my friend Sebastian Vettel. Okay, he let some races go awry, but fortunately he has caught up again.”
Ferrari have taken pole at every race since the summer break this season, but the last three have seen Mercedes take the race win through poor tactics and on-track errors from the red cars.
With the SF90 now a rival for Mercedes’ W10, Ecclestone says similar mistakes will not be tolerated next year.
“Ferrari has the strongest driver duo in 2020,” he said.
“But you have to be able to perform at the highest level. Especially when the best car finally comes from Maranello!”