World champion Sebastian Vettel said Monday his back-to-back title triumphs in the last two years would count for little when the 2012 Formula One season gets underway in Melbourne on March 18.

On the day when Red Bull used the internet to unveil their new “fourth generation” RB8 car, the 24-year-old German took the time out to dwell on his hopes of making it a hat-trick of world titles.

“It’s difficult to say (what will happen). Every season we start from zero again,” Vettel said.

“Unlike other sports, in tennis for instance, you’re the number one in the world and there is a certain gap between you and the number two.

“Until we put them (the cars) on track to race each other we don’t really know.”

Team-mate mark Webber will have the first drive here on Tuesday and Wednesday with Vettel taking over for Thursday and Friday.

Vettel had his second world title last year sown up by early October with three races still to go. Webber went on to take third place.

Together, their all-conquering Red Bulls dominated the constructors championship, finishing well ahead of McLaren and Ferrari.

Their performances prompted Formula One supremo Bernie Ecclestone to declare that he would prefer if there was more of a competition in the sport and Vettel agrees that he has set himself near impossibly high standards.

“We know how hard it is to be that consistent, always there and finishing nearly every race on the podium.

“Obviously we hope our car is better than all the others, but it will be difficult because the cars will be fairly similar, with the gaps closer than they have been.”

The new RB8 car, designed by Adrian Newey and unveiled on the internet, showed it to have the same “platypus” snubbed nose as all the other cars this season with the exception of McLaren.