Ferrari’s Charles Leclerc beat Red Bull's Max Verstappen into second spot in Australian Grand Prix practice on Friday – as Lewis Hamilton laboured and Alex Albon crashed his Williams spectacularly.
Reigning world champion Verstappen has won the first two races of the season and is aiming to match his record of 10 consecutive victories this weekend.
But Leclerc finished 0.381 seconds faster than his rival in Melbourne as his Ferrari teammate Carlos Sainz was third after returning from surgery on his appendix.
Lance Stroll and Fernando Alonso of Aston Martin were fourth and fifth, with Mercedes' George Russell in sixth.
Hamilton ended up down in 18th place and claimed there was “something was wrong” with his car.
Leclerc said afterwards: "It feels good for now. We had a positive day.
"It's a good start but we need to keep working very hard because I'm sure we will see some surprises tomorrow. I would say we are in a better position than in the first two races. However. Red Bull weren't pushing yet.
"I think they are still ahead but we may have our best shot since the beginning of the season."
Verstappen was unable to match Leclerc's pace and said: "It was alright. Ferrari is quick but there are a few more things we can fine-tune. Nothing crazy, nothing worrying, just need to fine-tune the car."
After a challenging day, Hamilton said: "I don't feel great. One of the worst sessions I've had for a long time. The car in P one felt the best it's ever felt and then it got worse and worse. We made some big changes on P two and it was tough."
Leclerc’s Ferrari teammate Sainz – back in his cockpit following British teenager Ollie Bearman’s stand-in drive in Saudi Arabia a fortnight ago – managed well to finish in third.
There was concern about how his body would fare after his surgery but he said he felt "reasonably comfortable".
"I will continue to take it step by step to make sure I come to qualifying and to the race in the best form possible," said the Spaniard.
“It’s been a couple of tough weeks leading to today and to be honest I’m very happy I could complete both sessions with reasonable comfort."
Williams driver Albon missed the second session after he lost control of his car on the exit of turn six and smashed into the safety wall.
The British-born Thai driver, 27, was taken to the medical centre for precautionary checks as the session was red-flagged to clear his destroyed machine.
Albon’s right-front wheel tore off his Williams, with debris littering the track.
He came to a standstill and was able to get out of his cockpit. “Sorry,” he said over the radio before he was taken away in the medical car.
He will drive teammate Logan Sargeant's car for the rest of the weekend as his chassis is too badly damaged to repair.
“Muchos debris,” said McLaren's Lando Norris. “Is he alright? It looked pretty large.”
Norris also had issues. He finished first in the opening session but was only ninth in the second.
Elsewhere, home favourite Oscar Piastri finished seventh, two positions ahead of Norris in the other McLaren, in front of a record 124,000-strong crowd.
