Charles Leclerc led a Ferrari 1-2 at the top of the timesheet in the Australian Grand Prix's first practice, while defending champion Lando Norris suffered a gearbox issue as Formula One's new engine era launched with a spate of reliability problems.
Leclerc lapped a sun-bathed Albert Park in one minute 20.267 on soft tires on Friday, nearly a half-second quicker than second fastest teammate Lewis Hamilton, the seven-times world champion. Four-times champion Max Verstappen was third fastest for Red Bull, 0.522 seconds behind Leclerc, with Verstappen's new teammate Izack Hadjar fourth.
Constructors champions McLaren had a sobering start, with Norris complaining his downshifts were "shocking" in his opening lap.
He cut his session short after managing to clock only the 19th fastest lap on medium tires.
His teammate Oscar Piastri was sixth quickest on soft tires, but nearly a second behind Leclerc's best.
He also came to a halt, reporting a throttle problem in his first lap before he was able to get going again.
Ferrari and Red Bull rose above the initial chaos, posting clean early laps and setting the pace on medium tires.
Racing Bulls rookie Arvid Lindblad triggered a safety car less than four minutes into the session when he came to a halt in pit lane and needed to be rolled back to the garage by team mechanics.
However, the 18-year-old came back strongly to record the fifth fastest time. Williams driver Alex Albon also lost power and stopped on the track late in the session, prompting the second virtual safety car.
The new hybrid engines, which feature a much larger share of electric power than in the previous era, have proved a steep learning curve for drivers, placing a greater onus on managing energy deployment and regeneration.
Having barely clocked any laps during winter testing due to reliability issues, Aston Martin's troubled start continued as Fernando Alonso was unable to leave the garage due to a suspected power unit problem.
His teammate Lance Stroll could manage only three laps on hard tires, the best (1:50.334) more than 30 seconds behind Leclerc. Though strong in winter testing, Mercedes' George Russell was seventh fastest ahead of eighth-ranked Kimi Antonelli.
Rebooted F1 team Audi, formerly known as Sauber, started well, with Gabriel Bortoleto and Nico Hulkenberg ninth and 10th quickest in the session.
New team Cadillac's first session in Formula One was underwhelming, though Valtteri Bottas racked up 24 laps and the 17th fastest lap.
Teammate Sergio Perez was 20th quickest.
