F1 2014: Expect the unexpected!

The prospect of seeing Sebastian Vettel beaten for the first time since last July is just one of the many novelties Sunday's season-opening Australian Formula One Grand Prix promises to deliver.

Just how much trouble Vettel's Red Bull team might be in is one of the questions waiting for an answer as the sport's unpredictable new turbo era whooshes into action at Melbourne's Albert Park circuit.

The quadruple world champion won the last nine races of 2013 but the 26-year-old German spent much of his time during the pre-season tests in Spain and Bahrain watching the car being worked on in the garage.

Red Bull are braced for a reality check as they and partners Renault work against the clock to fix the troublesome 1.6 litre V6 hybrid turbo engine and its complicated new energy recovery systems.

Rivals Mercedes, under new leadership following the departure of Ross Brawn, have been racking up the laps with far less hassle.

"Mercedes have got a bit of a march on people. They invested more, they invested earlier. They've got themselves into a good position," Red Bull team principal Christian Horner told reporters.

"If Mercedes were to finish two laps ahead of the opposition in Melbourne, that wouldn't be a surprise, based on what we've seen in pre-season testing. It's massive.

"From what we can see at the moment, all the Mercedes powered teams are in pretty decent shape and we're not.

"We're on the back foot, and have a lot of ground to catch up," added the Briton, who now has Australian Daniel Ricciardo in the lineup following compatriot Mark Webber's retirement.

Horner's words may be a part of the pre-season mind games, repositioning Red Bull as underdogs but Mercedes drivers Lewis Hamilton and Nico Rosberg have sounded quietly confident about a car that is sleeker than many of its 'ugly' new-look rivals.

"With all the changes within the sport and the hard work that's been going on within the team, I believe this can be our year to really show what we're capable of," said Hamilton, the 2008 world champion with McLaren.

"I feel like I'm equipped with the tools I need to succeed. I can't wait to get started," added the Briton, whose win in Hungary last July was the last by anyone other than Vettel.

Ferrari will be hoping to challenge with their new lineup of champions following the return of Finland's 2007 title winner Kimi Raikkonen - triumphant in Melbourne for Lotus last year - to partner Fernando Alonso.

The cars will sound different without the old V8 engines and will also be far less reliable at first, with any repairs likely to take far longer due to the complexity of the power units.

How many cars will start from the grid, let alone finish the race now that fuel economy is a big factor, is another uncertainty. Some insiders have predicted that Sunday evening could see less than half the field reach the chequered flag.

In 1996, when Melbourne first hosted the grand prix, only 11 cars made it to the finish in a race won by Britain's Damon Hill in a Williams.

That team had a nightmare season last year, the former champions taking only a meagre five points and finishing ninth overall, but they are more optimistic now they have switched Renault power for Mercedes.

Brazilian Felipe Massa, who has joined Williams from Ferrari, lapped faster than anyone in Bahrain testing and was able to put in plenty of laps.

"The new car we have is really well built, good quality... it is very reliable and not slow either so it's going to be an exciting season," Finnish driver Valtteri Bottas told Reuters.

"Like I've kept saying for a couple of years now, I really think the future of Williams is going to be good and hopefully this can be a step forward from other years."

McLaren, starting their last season with Mercedes before the switch to Honda, are also looking for a strong start after failing to step on the podium at all last year and ousting principal Martin Whitmarsh.

Jenson Button, who spoke movingly last week of how much he will miss his father in the first race since his death in January, has an exciting new team mate in 21-year-old Danish rookie Kevin Magnussen.

"We're not the quickest," said the 2009 champion, who has won in Australia three times in the last five years. "We're looking at Q3 (qualifying in the top 10) and then a very good points finish at the end, if we can get to the end."