Portugal Colonial - Miller tops opening practice at Australian MotoGP ahead of Marquez

Yamaha-Pramac rider Miller clocked a last-gasp blistering lap of 1min 28.281sec around the waterfront Phillip Island circuit in blustery but dry conditions.

That put him 0.036sec clear of Marquez on his Ducati-Gresini, with KTM's Pedro Acosta third ahead of rookie Fermin Aldeguer, who won the Indonesia MotoGP a fortnight ago.

Spain's Marquez has an 88-point lead over two-time world champion Francesco Bagnaia in the battle to clinch second place in the standings with four rounds left.

He can do so by finishing the weekend 111 points clear of his Italian Ducati rival, who failed to score a point in Indonesia just a week after winning the Japan MotoGP and sprint races.

Bagnaia's Australia weekend didn't start well, back in the pits after one flying lap, gesturing about the bike shaking. He returned to finish seventh, 0.275sec adrift of Australia's Miller.

Marquez's dominant brother Marc, the recently-crowned world champion and last year's Phillip Island winner, is not in Australia after shoulder surgery.

Also missing is 2024 polesitter Jorge Martin, who is still recovering from a fractured collar bone sustained in Japan.

Italy's Marco Bezzecchi, who won the Indonesia sprint before slamming into Marc Marquez during the grand prix, came sixth.

Bezzecchi must serve a double long lap penalty on Sunday for causing the Marquez incident.

Ducati-VR46 rider Franco Morbidelli was the first faller of the weekend, losing his front end at turn one, while Honda's Joan Mir called time early with thick smoke bellowing from his exhaust.

The second practice session, from which the top 10 riders go straight into Saturday's second round of qualifying, gets underway at 3:00 pm (0400 GMT).

Qualifying shapes the grid for both the sprint race on Saturday and the main event GP on Sunday afternoon, with a maximum of 37 points available.

X.Matos--PC