Defending champ Vettel wary of Webber threat

World champion Sebastian Vettel insisted on Sunday that he is not the overwhelming favourite for a fourth successive Formula One title and believes his main threat could come from Red Bull teammate Mark Webber. The season roars into action on March 17 in Melbourne, with 19 races scheduled over nine months with the season closer in Brazil on November 24. "It's one thing to look back at what we have achieved as a team, but really I feel that we all start again from zero," said Germany's Vettel, who became the youngest man to win three straight titles in 2012 at the age of 25. "So we've all got the same chances and it will be a long year, a lot of races and a very tough challenge waiting for all of us. "If anything the expectations are there, people expect something, but more than that, we expect ourselves to do well again so there's a lot of pressure. "It will be tough -- tough to beat Mark (Webber), tough to beat the other guys and the other teams because they will try everything to beat us. "The best drivers are in the best teams. I think it's easy for you to work out who they are -- Fernando (Alonso) certainly is one of them. "Mark is one of them, Lewis (Hamilton) is one of them and there are others, but I usually don't like to name them as there's a chance of forgetting one of them and that's not the idea. I think it's the usual suspects." Red Bull unveiled their car for the new season on Sunday with team boss Christian Horner saying the desire for more success is as great as ever. "As always the competition is phenomenal, so to have won three in a row is quite remarkable. It's testimony to all the hard work that has gone on," said the 39-year-old. "We're still a young team, but we're evolving and there is a fierce determination to keep those trophies for another year." Horner also defended recent criticism by team advisor Helmut Marko who questioned Webber's capacity of maintaining a season long challenge for the title. Horner said they are happy to have extended the contract of Webber, who has won only three races in the last two seasons. "As we all know Helmut can be outspoken at times and some of his comments, that reflected his opinion, and sometimes these things can be misinterpreted," Horner said. "If we weren't happy with Mark we would never have signed him for this year. We give both drivers equal opportunity and it's down to what they do on the circuit. "Certainly in the team, that's the approach and we'll continue to do that. For us, it doesn't matter which driver wins as long as it's in one of these cars." The 36-year-old native of New South Wales also said he was confident he could beat Vettel to the title. "I do believe I can have a crack at the championship again this year, as I have done in previous seasons," he said. "That's what I'm getting up each day thinking. The team know I need 100 per cent support. You cannot win world championships with 90 per cent support. That's what I'm confident of." From AFP