Having won three races so far this year, Ferrari is eager to make a push for 2016 to fight Mercedes head-on for the world championship.

And although Vettel knows nothing is guaranteed until its new car hits the track in testing next February, he is optimistic the work being done back at the factory will pay dividends.

"It is always difficult to predict what is going to happen but surely it is our target," said Vettel about title ambitions in 2016.

"Surely I can see what is happening in the background, the work that has gone into this year, and the work that is going in to next year, back at the factory in Maranello.

"It looks promising, and we should be able to make a good step forward.

"But the most important day is when you put the car on the track and see what it does. We have two races left and ideally we want to get the best possible results here and in Abu Dhabi."

Lauda comments

Vettel also welcomed comments from Niki Lauda that Ferrari's engine was a match for Mercedes, as he suggested it highlighted the growing threat from Italy.

"Niki is not the best one to trust because he changes his opinion very quickly," he said.

"Sometimes what he says makes sense and sometimes it doesn't make sense.

"But the more he talks about us the better, so maybe he can feel us coming - which is good news."

Second still the target

After retiring from the Mexican Grand Prix, Vettel slipped behind Nico Rosberg in the fight for second place in the championship behind Lewis Hamilton.

But he remains determined to finish the year as runner-up.

"There are two races to go, last one didn't help, but as long as it is possible to finish second you want to finish second rather than third," he said.

"So our target is to at least split the Mercedes and split them the right way. The best way to do that is to do our job and try to achieve our maximum, and we see what happens on Sunday."

Watch our preview of the Brazilian GP: