Jackie Stewart contends that it's more difficult to defend the world championship than to win it for the first time; that after you reach the pinnacle once, you can struggle. In the case of Mika Hakkinen, my title-winning McLaren team-mate in 1998 and '99, he went away at the end of the season elated with his first title, but he was deflated in the first part of the following year before he rebuilt the energy to go for it again.
Button has edged ahead of Hamilton this year © LAT
So what Sebastian Vettel has done in winning back-to-back world championships in so dominant a style is remarkable. It's as if being champion last year has allowed him to unlock something and move to another level. He does make mistakes - and there have been crashes during Friday practice, as we saw at Suzuka - but very few. He's stepped up, while by contrast Mark Webber has struggled and never had the rub of the green.
Qualifying at Suzuka was a great example. It seemed that McLaren had the edge, but Seb dug deep and delivered an incredible qualifying lap. He is absolutely focused, is not living the rock-'n'-roll lifestyle, and that's reflected in his performances. And there are more wins to come, even though he couldn't clinch the title with the victory he wanted.
The fight for second