Sebastian Vettel admits his string of three consecutive Formula 1 world championships brings its own set of pressures and distractions which could damage his 2013 prospects.

The German beat Ferrari's Fernando Alonso the 2012 crown by just three points after surviving an opening-lap shunt in a wild Interlagos finale.

And while Alonso has tipped Red Bull to once again start the year as favourite, Vettel insists he and the team will keep to their methodical approach in order to avoid losing momentum.

"I said after [Brazil] race that the hardest thing is to win after you have [already] won," Vettel said in relation to his prospects of a fourth F1 crown.

"You get the attention and the pressure, and you are very likely to focus on how to win again, rather than the small steps [needed] to win in first place.

"Of course there's pressure, [and] on top of that it's always getting more and more tense at the end of the year, within the last couple of races depending on who you fight in order to try to win the championship.

"Obviously we have won the championship [in 2010 and '11] and this year again, so I don't want to praise ourselves, but I think we have done a couple of things right."

In the immediate aftermath of clinching the 2012 title, Vettel had decried the use of 'dirty tricks' which had played against his outfit over the course of the campaign.

Vettel said his methodical approach had helped guard against becoming preoccupied with such issues.

"It's not our decision or in our hands when other people try literally everything to beat us," he explained.

"There might just be a little bit of a rumour; other things might get said; and other things might happen eye to eye without any words, without you having to mention anything.

"It's not easy to stay focussed in that regard - it's very, very hard.

"Again the most important thing is to focus on yourself and to remain yourself.

"You don't try to be something you are not it just distracts and takes energy away."