As the opening race of the Formula One season, the Australian Grand Prix always is fraught with unknowns.
But this year's race on the 3.3-mile Albert Park layout in Melbourne on Sunday is especially unpredictable due to rules changes and a shuffling of some teams' drivers.
Among other things, the cars have gone from V-8 engines to turbocharged V-6 engines, the amount of fuel allowed during a race has been limited, the gearbox has been expanded from seven gears to eight and there are changes in various body parts including the nose and front wing.
All of which raises the question of whether Sebastian Vettel of the Red Bull team, who has won the last four consecutive Formula One titles, can capture a fifth championship.
In winning the title last year, the 26-year-old German driver won the last nine consecutive races. But in preseason testing this year, the Red Bull cars have struggled.
"We know that obviously we're not in the best shape yet," Formula One's website quoted Vettel as saying at a news conference in Melbourne on Thursday. "It's obviously a tough step for all the teams, all the drivers, a lot of new things to get used to."
Vettel this year has a new teammate, Daniel Ricciardo, who will debut in his native Australia.
The defending winner of the Australian Grand Prix is Kimi Raikkonen, who has joined another former champion, Fernando Alonso, at Ferrari after leaving the Lotus team.
But the fastest drivers in early practices in Australia have been Lewis Hamilton and Nico Rosberg of the Mercedes team.
Other changes for 2014 include awarding double points in the season finale to heighten the excitement surrounding the championship. Drivers also now choose what numbers to put on their cars, with the current champion -- in this case, Vettel -- given the option to use No. 1.