MELBOURNE (AFP) - Formula One enters a new and unpredictable era at Sunday's Australian Grand Prix after a change in engines and a limit on fuel left many drivers wondering whether they will reach the finish.
Britain's Lewis Hamilton will start the season-opener on pole after a thrilling qualifying session which most cars escaped unscathed, defying doomsday predictions of widespread mechanical failures.
However, 58 laps of the parkland Melbourne circuit will provide a severe test for the teams which are still adapting to the new, quieter 1.6-litre turbocharged V6 engines and their energy recovery systems (ERS).
And the great unknown is how drivers will manage the new 100kg limit on fuel, which represents about two-thirds of the loads consumed previously.
"It's going to be a long race tomorrow and reliability will be the most important thing to make it to the flag," warned four-time world champion Sebastian Vettel.
Illustrating the difficulties facing the teams, Mercedes' Nico Rosberg was seen slowing down and throwing something out of the cockpit during Saturday's practice after part of his equipment apparently became loose.
Red Bull's pre-season problems extended when an engine software issue hit Vettel in qualifying and the world champion finished outside the top 10 for the first time since 2012.
Add in the chance of rain, which fell heavily during qualifying, it promises to be an engrossing start to the 19-leg season - which will culminate, controversially, with double points on offer in Abu Dhabi.
Vettel has been the big loser so far from technical difficulties and he will start from 12th as he opens his bid for a fifth straight world championship and a record 10th consecutive win.
Lotus, hit by braking problems, endured a nightmare qualifying session with both of their drivers, Romain Grosjean and Pastor Maldonado, dropping out in Q1.
Hamilton remains the favourite in a Mercedes car which proved its reliability in testing, with his teammate Nico Rosberg expected to push hard from his starting position of third.
"The points are won on Sunday and we know that it will be a tough race in terms of fuel consumption and reliability," said Mercedes executive director Toto Wolff.
Red Bull's Daniel Ricciardo headed a list of young drivers who impressed on Saturday when he appeared to have taken pole position in the dying seconds, only to be quickly usurped by the flying Hamilton.
The 24-year-old Australian will start from second with McLaren rookie Kevin Magnussen fourth and Jean-Eric Vergne sixth after a hugely impressive qualifying session in his Toro Rosso.
"Getting onto the podium won't be easy, especially if it's dry. But if it's wet, anything could happen - so I guess a wet grand prix is what I'll be hoping for," Denmark's Magnussen said.
Two-time world champion Fernando Alonso is on the third row but there was an inauspicious start for his new Ferrari teammate Kimi Raikkonen after the Finn, last year's winner in Melbourne, hit a wall in qualifying.
McLaren's Jenson Button, the last man other than Vettel to win the world title, in 2009, also had a disappointing qualifying session and will get underway from the fifth row, halfway down the grid.