Sebastian Vettel, Red Bull, Barcelona testingWorld Champion Sebastian Vettel says he is not making any predictions for the upcoming season, insisting it is impossible to compare the performance of the cars.

The Red Bull driver finished the Barcelona test on top for the second day running, before handing his car over to teammate Mark Webber for the remaining two days. Despite his pace, Vettel said his team is focusing on its own performance, as he reckons there is no way to know how strong his rivals are.

"I don't see it all, because the championship hasn't started yet," he said of the outlook for the season. "It's winter testing, and everybody is trying to prepare. It's very hard to judge at this stage where you are, how quick the car is.

"You run through your program. This year with the new tires it is very hard to read the lap times and performance of the other cars, so I think we have to remain cool and focus on ourselves. Obviously, we try to improve the car as much as we can and then we'll see when we go racing and when the championship starts."

The German reiterated he will not change his approach for being world champion, and conceded the main focus has to be on the first few races rather than on defending the crown, even if that's his main goal.

"I think when we start in Bahrain, or somewhere else, we all start with zero points. It doesn't myself if it's me, Heikki [Kovalainen] or anybody else. We all start with zero points.

"Obviously, last year was very good for myself and for the team, and the target is there: we want to defend our championships, but it's a long way. I think it's wrong to start the season only focusing on the championship. We have to focus on the first couple of races, on our car and make it reliable and then very soon you will know how good the car is and if we have the chance to fight for the title or not."