Marc Marquez quickest in Australian MotoGP practice
Six-time world champion Marquez, a four-time winner at Phillip Island, clocked a blistering fastest lap of 1min 27.770sec around the waterfront circuit after early rain cleared.
The Spaniard finished 0.102sec clear of his brother Alex, both on Gresini bikes, in a session briefly interrupted by a goose on the track.
Italy's Marco Bezzecchi on his Ducati-VR46 came third ahead of Martin on a Pramac, the Spaniard edging his chief title rival Francesco Bagnaia into fifth.
With four race weekends left the championship is finely poised with Martin just 10 points ahead of Italy's Ducati defending champion Bagnaia.
Ducati's Enea Bastianini is 69 points adrift, two clear of Marc Marquez, with both needing podium finishes to stay in touch this weekend.
However, Bastianini could only finish 16th.
The riders finally fired up their bikes after the opening morning practice was cancelled without any action due to persistent heavy rain.
It was a headache for the teams who were keen for a dry day to gather data on what tyres were best suited to the newly resurfaced track.
The drenching stopped in time for the afternoon session, but disaster struck for Martin when he crashed on only his second lap after making contact with Fabio Quartararo.
Bagnaia also struggled, back in the pits early.
When both men returned, a red flag came out after a goose wandered onto the track to further complicate their efforts to clock competitive laps.
Marquez set the early pace before being dethroned by Maverick Vinales with 10 minutes left, but he roared back to take top spot as Martin and Bagnaia threatened.
Vinales, Brad Binder, Fabio Di Giannantonio, Franco Morbidelli and Alex Rins also secured their places in the top 10.
They all progressed straight through to Saturday's second qualifying, which shapes the first four rows of the grid for the sprint race and Sunday's main event.
The group will be joined by the fastest two in Saturday's first qualifying stint.