Stewart: I think Sebastian has passed his peak

Vettel's error-strewn season was not helped by his team who more than once shot themselves in the foot and as a result, the Reds have had to watch Lewis Hamilton's celebrations after the title was decided at the Mexican Grand Prix.

In the wake of Sunday's race, Stewart told Bild, "I think Sebastian has passed his peak and Lewis is still progressing. I add that there is no reason Sebastian cannot come back, but it will be harder for him after such a season he will become more critical of himself.

Asked if success came too soon for Vettel in Formula 1, Stewart reasoned, "Maybe. He came into Formula 1 at the age of 20 and was four times champion between the ages of 23 and 26 years. If you are less successful at a young age, you stay ambitious by setting yourself goals."

"His natural talent was so great and now he causes these collisions. You cannot constantly blame everyone else. If you fight for a world championship and you see, there could be a problem for you, then you cannot stab at it, you must wait for the right moment."

"I really like him very much, he is a very good driver, very emotional and technically maybe he is still the best, but he no longer appears to have that clinical mind like he used to."

"Lewis, on the other hand, continues to develop as a driver, add to that his success and he can be more relaxed," added Stewart.

Vettel has enjoyed unofficial 'number one' status at Maranello since his arrival in 2015, stats show that more often than not the German got the better of veteran teammate Kimi Raikkonen in the sister car.

Next year there will be changes at the Scuderia, highly-rated Charles Leclerc steps up to Ferrari to partner Vettel, setting the stage for an intriguing battle between the French young gun and the German elder statesman.

By this time next year, we will know if Sir Stewart is correct in his assessment that Vettel is now over the hill...