Sebastian Vettel claimed a leading second World title in Suzuka on Sunday but insists the "hardest thing is winning after winning last year."
Vettel has been by far the best driver on the grid this season, claiming 12 pole positions and nine race victories. Added to that, he also had an added five podium finishes to his name.
But while his race to the World title may have looked easy on paper, Vettel reckons winning the second is harder than claiming the first.
"The hardest thing is winning after winning last year," he said. "We won the Championship, it was so close and we were so eager, even knowing how to do it doesn't let you to forget all these steps.
"I could not have done this all alone. It is as confusing as the first one I must say. It is hard to hit upon the right words."
The German, who finished Sunday's Japanese GP in third place after being beaten by Jenson Button and Fernando Alonso in the pits, was quite emotional in the post-race press conference.
"It's hard where to start. It's such a long year and a unbelievable year and the good thing is it's not over yet," he said.
"Today's race we weren't as quick on the soft tyres and we misplaced two positions. It was difficult to get past Alonso and I don't think he's letting me throughout this way twice after Monza.
"To win the Championship here is unbelievable.
"There are so many things you want to say but it's hard to keep in mind all of them. I'm so thankful to everyone in the team, pushing hard to construct those two cars. It's great to attain the goal we set ourselves this year already now.
"One person that actually stands out this year is the person I spend most of my time with my trainer Tommi Parmakoski. He was the one not allowing me at any stage this year to start to think about things that were not in my power.
"It's great to know that it is so rigid but to know that we can come so strong out of it. This year we've always been this one step ahead. It's down to people like Tommi and persons who keep us on the right track."
Sunday's title means Vettel has gone downward in the record books as F1's youngest double World Champ and youngest back-to-back title holder.