Sebastian Vettel says he is not going to leave Ferrari just because his 2018 title campaign is in tatters.

Not long ago, the German looked set to use his superior red car to claw back ground against Mercedes' Lewis Hamilton.

But in Monza, Singapore, Russia and now Japan, not only did Ferrari's mistakes reign, but the Maranello team's formerly superior 2018 car dropped steadily behind.

Nonetheless, Vettel said before leaving Suzuka: "I will not leave Ferrari.

"I'm part of the team and I want that to be the case and nothing else," Germany's Auto Bild quotes him as saying.

"I think we have a lot of potential. Of course, the last races did not go well for us and we made it too easy for Mercedes. But even so the spirit within the team is good."

However, Vettel acknowledges that the championship is now looking all but mathematically impossible.

"Of course we know that it is difficult now," he said. "But what else do we have to lose?

"We will give everything and there are still important things we can learn and understand about the car."