With the 2012 Formula One season set to get under way in Melbourne on March 18, AFP Sport looks at world champion Sebastian Vettel's five main rivals for this year's title.

Formula 1 in 2012 has been primed as one of the most open seasons we've seen yet. The new regulations implemented in the sport has seen to it that cars are a little more level in terms of pace than we've ever seen before.

But this in mind, it's still a difficult situation to cast any doubt of Sebastian Vettel running away with the title for a third season in a row now. The German double-World Champion is on top of his game, and Red Bull Racing have established themselves as a team never too far away from having the best car on the grid.

However, there are yet a few men who have it well within themselves to break Vettel's streak - should things come together for them throughout the season.

So here's a look at five candidates and potential Vettel-mania enders in this year's Formula 1 season.