MELBOURNE - Despite being separated by just three points at the dramatic culmination of their World Championship duel in 2012, title rivals Fernando Alonso and Sebastian Vettel have predicted an even closer contest at the front of the grid in the new F1 season.Definitive, fence-defying predictions have been a rarity since the sport set up camp in Melbourne for Sunday’s season-opening race. With reigning World Champion Vettel describing winter testing as the "most inconclusive” he has ever experienced, a concurring Alonso believes that as many as ten drivers have a realistic shot at victory around Albert Park."Nobody knows who can win this race, we will just have to wait and see,” said the Spaniard. "These are questions that winter testing didn’t answer."This year, there is some consistency through the grid and I expect the five top teams to have a little advantage, but of those five teams, it is very difficult to say after winter testing which of them will have the extra two or three tenths which could make them win."I think Mercedes, Ferrari, McLaren, Lotus and Red Bull all showed potential at different times during testing, so it’s hard to choose. It’s very close and difficult to choose one favourite.”The prevailing impression from trackside at the final Barcelona test was that Vettel’s new Red Bull car perhaps possesses a small but useful advantage over the rest of the field, with the RB9 thought to be around two-tenths faster than a closely-matched group containing the Ferrari, Mercedes, Lotus and McLaren.That notion of the pecking order, though, remains unproven, and, other than revealing that he did not use the new supersoft tyres during winter testing, Vettel gave little away when he faced the world’s press in Thursday’s Drivers’ Press Conference."We don’t really think about what has happened last year, we are here with zero points on our side, the same as everyone else. The cars haven’t really changed and we saw last year that it was very close so I don’t expect it to be very different to last year."If anything, it will be a little bit tighter so it will be crucial to make the most of every single race.”Alonso’s own prospects have been boosted by Ferrari’s improved performance during winter testing - at least compared to their travails of twelve months ago when the F2012 was born almost two seconds off the pace."It’s not difficult to start better than 2012, but it would be difficult to start worse,” added the Spaniard. "It is going to be a very interesting championship, we need to start on the right foot.”Yet while Ferrari have apparently stepped forward, and hopes abound that the Red Bulls haven’t sped clear of the pack, one extra fascinating ingredient likely to be thrown into the race-contending mix along with the Lotus and McLaren is the Mercedes W04.Both Lewis Hamilton and the 2008 World Champion’s new team-mate Nico Rosberg topped the timesheets on the final weekend at Barcelona and the Silver Arrows new recruit is already looking comfortable in his new surrounds."Normally when you go to a new team it takes a while to get settled in, but I’m working as hard as I can to get settled in,” said Hamilton. "It just takes time and as time goes on I will get more comfortable.”More pertinently, Hamilton also feels settled in his new office."I’m comfortable in the car. We’ve definitely made some good steps forward, but we have a lot of work still to do.” Quite how much will be revealed on Sunday.