Three-time defending champ Sebastian Vettel the favourite as F1 season starts in Australia

PARIS - Preseason testing has been surprisingly subdued for Red Bull's Formula One team, which has struggled to top the time sheets and left cynics wondering whether Sebastian Vettel's reign as champion is about to end.

Don't count him out just yet.

The three-time defending champion has been in this situation before. In 2012, he roared back with a string of victories toward the end of the season to overtake Ferrari's Fernando Alonso and win the title in Brazil. And many believe the team's 2013 car has yet to show its full potential as Vettel and teammate Mark Webber prepare for the Australian Grand Prix on March 17.

For Vettel, the 25-year-old German driver known for his boyish charm, it's a chance to make history once again. Winning a fourth consecutive title would put him in the company of F1 greats Manuel Fangio and Michael Schumacher. Fangio won four in a row starting in 1954 and Schumacher won five of his record seven overall titles from 2000-2004.

"Well, it's not that we believe that we will go to Melbourne and blitz everybody," said Vettel, the youngest triple champion in F1 history. "We are happy with the balance and the way the car behaves — and that is a very positive signal — but whether that is enough or not we do not know at this stage. I would say that there is still work to do."

Vettel's modesty is in sharp contrast to several other teams and their drivers who are brimming with confidence, none more so than two-time champion Alonso. This time around he is driving a much-improved vehicle and the Ferrari fans are starting to talk about winning a title for the first time since 2007.

"If I think back to last year, my state of mind was very different: we knew we were two seconds off the pace, we were all pessimistic and worried," Alonso said. "I think we are on the right road to being closer to the quickest, which will be our aim in Melbourne."

But even the 31-year-old Spanish driver is not reading too much into Ferrari's strong preseason testing results.

"It's like watching football training: you can't believe that a reserve Real Madrid forward can be a contender against Barcelona just because he scores a goal in a kick-about," Alonso said.

He is just one driver who comes out of preseason testing with a bit of momentum.

Lewis Hamilton has the speed and daring to beat Vettel but the British driver must get used to his new car after switching from McLaren to Mercedes. Early signs in testing are that the British driver has adjusted well to his new surroundings and found the new car to his liking — that is after his first drive ended abruptly when he slammed into a barrier after the brakes failed.

"There's still a lot of work ahead of us to get to where we want to be but the team is doing a great job," said Hamilton, whose move to Mercedes ended an often tense relationship with fellow driver Jenson Button.

Button will be among what is considered as the next level of contenders, along with Webber and Kimi Raikkonen, who returned to F1 in style with a victory in Abu Dhabi and will be seen as the dark horse in the title chase.

Red Bull team principal Christian Horner dismisses suggestions that his team has any kind of edge, insisting there are several teams — Ferrari, Mercedes and Lotus — which could pose a threat to their championship aspirations.

"We have won three double world championships now. That is in the record books, nobody can take that away from us, so that in many respect removes pressure on us and puts it on others," Horner said. "But we put pressure on ourselves because we want to continue to run in the front and defend both of those championships, so I would say the team has evolved extremely well over the past three years. We are well placed for the future."

In the end, Vettel's success will come down as much to his driving skills as the team's ability to keep his car on the circuit. Consistency has long been Red Bull's strong point, particularly last year where the likes of Hamilton and Alonso saw their title hopes dented by crashes or mechanical problems.

But with questions still unanswered over everything from the speed of the Red Bull to the performance of tires, Vettel said it's too early to start talking about another title.

"I think Melbourne will show the trend, but I doubt that we will be able to establish any real pecking order based on one or two races," Vettel said. "Last year we also had to learn that it takes much longer these days to know who is hot and who is not."