Brazilian GP: Sebastian Vettel struggles with three-title tag

Red Bull's Sebastian Vettel said he was finding it difficult to come to terms with the fact that he had joined the ranks of three-time champions.

The 25-year-old German was sixth at the Brazilian Grand Prix to become the ninth driver to win three titles.

He is only the third after Argentine Juan Manuel Fangio and German Michael Schumacher to win three in a row.

"To win that third title here, where one of my greatest idols Ayrton Senna was from, is unreal," Vettel said.

"It's very difficult to imagine I join him and other great names in winning three titles."

Vettel, who is a keen fan of F1 history, said he could not compare this championship with his previous two.

In 2010, he made up a 15-point deficit on Ferrari's Fernando Alonso at the final race, while in 2011 he dominated the season and won with four races to spare.

This year, the Red Bull has always been a strong race car but the team struggled to make it work consistently in qualifying until a major upgrade at the Singapore Grand Prix at the end of September, from which he won four races in a row.

Those results, and Alonso's retirement from the Japanese Grand Prix, turned around a 39-point deficit to the Spaniard into a lead for Vettel by the Korean race in mid-October.

"[It's] always difficult to compare," he said.

"It was a very, very tough season for us, on track, off track - a lot of ups and downs for everyone," he said.

"But we always remained ourselves and kept doing it our way and that made the difference in the end."

He added that he felt his rivals had resorted to underhand methods to try to destabilise Red Bull - although he did not specify what those were.

"It is unbelievable but the most important thing is that throughout the season we always kept believing in ourselves," he said.

"A lot of people tried to play dirty tricks but we did not get distracted by that and kept going our way, and all the guys gave a big push right to the end.

"We stepped up our game in the second half of the season, which allowed us to come back in this championship.

"I have to thank all the team because there is no-one in our team more important than the next person. We are all a group and fighting next to each other and not against each other. I am very proud of that. It is unbelievable.

He added: "For me it is always most important that you are happy with what you see in the mirror. You are honest with yourself because what is the point in trying to fake something else? You are always the first one to know if you are cheating yourself.

"In that way, I think people tried everything - inside the lines, outside the lines - to beat us.

"The amount of questions we had to deal with, stuff we had to deal with throughout the season, did not make our life easier but the key was to remain ourselves and that made the difference in a way.

"I am not holy. I have my mistakes like everyone else has. But I was brought up to be honest and I also believe that was the reason why we succeeded."

Red Bull were involved in a series of controversies over the technical regulations in the first half of the season.

Vettel added that he was committed to Red Bull and saw no reason to think about leaving.

"I have a contract until 2014. I don't think this story is over yet - I'm very happy and committed to give the best in the next years with them. I don't see any point thinking of another team or something else.

"It's incredible what we have achieved."