- Sebastian Vettel is motivated to challenge for a fourth straight F1 world title
- The German has won the drivers' championship in each of the last three seasons
- The Red Bull driver is confident the team are in better shape than this time last year
- The 2013 Formula One season begins with the Australian Grand Prix on March 17
Triple Formula One world champion Sebastian Vettel has warned his 2013 title rivals that Red Bull are in better shape than this time 12 months ago.
Red Bull driver Vettel edged out Ferrari's Fernando Alonso at the final race of the 2012 season to clinch a third successive drivers' title by just three points, while his team celebrated a third constructors' crown in a row.
Vettel, the sport's youngest ever three-time champion, insists the whole team is focused on matching last year's achievements.
"What we have is more or less the same car that we had in Brazil (the final race of the 2012 season) -- with some steps forward," the 25-year-old told F1's official website after taking to the track at a preseason testing event in Barcelona.
"But from a personal level I can say that I am much happier now than I was one year ago."
The German also dismissed suggestions he might struggle for motivation ahead of the 2013 season.
"Thank God I don't have to think about something like 'finding motivation!'" added Vettel.
"Sure it was nice what we've achieved in the last three years and it makes us all proud, but I would say that I am still in a phase of my life where I look forward, and that's the right direction to go."
Last season began in unpredictable fashion, with an unprecedented seven different drivers winning the season's opening seven races.
It was an uncharacteristically slow start to year from Red Bull, with Vettel winning the year's fourth grand prix in Bahrain but then not picking up a second success until September's race in Singapore.
"I don't think it will be much different from what was important last year -- again it will be very close, so it will not be a case of two or three drivers fighting it out," continued Vettel.
"In the first half of the season I expect a very similar situation to 2012 where we saw many different winners. Then, in the second half, some favourites will become visible.
"To be one of them you have to score points at every race and be consistent -- that was what got us the title in 2012."
Alonso, a two-time drivers' champions, made first appearance of preseason in Catalunya on Tuesday, but Vettel remains focus on ensuring Red Bull arrive at the season-opening Australian Grand Prix on March 17 in the best possible shape.
"When you drive and you see another car on the track it is almost impossible to notice details, from whatever car," said Vettel.
"This is much easier when you look at photos. To be honest right now we are still in the phase where we are fully concentrating on ourselves, not looking left and right."