Sebastian Vettel claimed a dominant 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 additional 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 excited, even knowing how to do it doesn't allow 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 find 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 rather emotional in the post-race press conference.
"It's difficult where to start. It's such a long year and a fantastic 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 lost two positions. It was difficult to get past Alonso and I don't think he's letting me through this way twice after Monza.
"To win the Championship here is fantastic.
"There are so many things you want to say but it's hard to remember all of them. I'm so thankful to everyone in the team, pushing hard to build those two cars. It's great to achieve the goal we set ourselves this year already now.
"One person that really stands out this yaer 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 control.
"It's great to know that it is so tight 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 individuals who keep us on the right track."
Sunday's title means Vettel has gone down in the record books as F1's youngest double World Champ and youngest back-to-back title holder.